diff --git a/msbuild/Xamarin.Mac.Tasks/Xamarin.Mac.ObjCBinding.CSharp.targets b/msbuild/Xamarin.Mac.Tasks/Xamarin.Mac.ObjCBinding.CSharp.targets
index ef31d5bda8..f339d83d53 100644
--- a/msbuild/Xamarin.Mac.Tasks/Xamarin.Mac.ObjCBinding.CSharp.targets
+++ b/msbuild/Xamarin.Mac.Tasks/Xamarin.Mac.ObjCBinding.CSharp.targets
@@ -74,12 +74,14 @@ Copyright (C) 2014 Xamarin Inc. All rights reserved.
 			CoreSources="@(ObjcBindingCoreSource)"
 			DefineConstants="$(DefineConstants)"
 			EmitDebugInformation="$(BTouchEmitDebugInformation)"
+			ExtraArgs="$(BTouchExtraArgs)"
 			GeneratedSourcesDir="$(GeneratedSourcesDir)"
 			GeneratedSourcesFileList="$(_GeneratedSourcesFileList)"
 			Namespace="$(Namespace)"
 			NoStdLib="$(NoStdLib)"
 			OutputAssembly="$(OutputAssembly)"
 			ProcessEnums="$(ProcessEnums)"
+			ProjectDir="$(MSBuildProjectDirectory)"
 			References="@(ReferencePath);@(BTouchReferencePath)"
 			TargetFrameworkIdentifier="$(TargetFrameworkIdentifier)"
 			FrameworkRoot="$(XamarinMacFrameworkRoot)"
diff --git a/msbuild/Xamarin.MacDev.Tasks.Core/Tasks/BTouchTaskBase.cs b/msbuild/Xamarin.MacDev.Tasks.Core/Tasks/BTouchTaskBase.cs
index 8d80082200..ef143d8fab 100644
--- a/msbuild/Xamarin.MacDev.Tasks.Core/Tasks/BTouchTaskBase.cs
+++ b/msbuild/Xamarin.MacDev.Tasks.Core/Tasks/BTouchTaskBase.cs
@@ -42,6 +42,8 @@ namespace Xamarin.MacDev.Tasks {
 
 		public bool EmitDebugInformation { get; set; }
 
+		public string ExtraArgs { get; set; }
+
 		public string GeneratedSourcesDir { get; set; }
 
 		public string GeneratedSourcesFileList { get; set; }
@@ -54,6 +56,9 @@ namespace Xamarin.MacDev.Tasks {
 
 		public bool ProcessEnums { get; set; }
 
+		[Required]
+		public string ProjectDir { get; set; }
+
 		public ITaskItem[] References { get; set; }
 
 		public ITaskItem[] Resources { get; set; }
@@ -83,9 +88,11 @@ namespace Xamarin.MacDev.Tasks {
 		protected override string GenerateCommandLineCommands ()
 		{
 			var cmd = new CommandLineBuilder ();
+
 			#if DEBUG
 			cmd.AppendSwitch ("/v");
 			#endif
+
 			if (NoStdLib)
 				cmd.AppendSwitch ("/nostdlib");
 			cmd.AppendSwitchIfNotNull ("/compiler:", CompilerPath);
@@ -98,6 +105,7 @@ namespace Xamarin.MacDev.Tasks {
 					dir = Path.GetDirectoryName (BaseLibDll);
 				else
 					dir = null;
+
 				cmd.AppendSwitchIfNotNull ("/lib:", dir);
 				cmd.AppendSwitchIfNotNull ("/r:", Path.Combine (dir, "mscorlib.dll"));
 			}
@@ -185,6 +193,38 @@ namespace Xamarin.MacDev.Tasks {
 
 			cmd.AppendSwitch (GetTargetFrameworkArgument ());
 
+			if (!string.IsNullOrEmpty (ExtraArgs)) {
+				var extraArgs = ProcessArgumentBuilder.Parse (ExtraArgs);
+				var target = OutputAssembly;
+				string projectDir;
+
+				if (ProjectDir.StartsWith ("~/", StringComparison.Ordinal)) {
+					// Note: Since the Visual Studio plugin doesn't know the user's home directory on the Mac build host,
+					// it simply uses paths relative to "~/". Expand these paths to their full path equivalents.
+					var home = Environment.GetFolderPath (Environment.SpecialFolder.UserProfile);
+
+					projectDir = Path.Combine (home, ProjectDir.Substring (2));
+				} else {
+					projectDir = ProjectDir;
+				}
+
+				var customTags = new Dictionary<string, string> (StringComparer.OrdinalIgnoreCase) {
+					{ "projectdir",   projectDir },
+					// Apparently msbuild doesn't propagate the solution path, so we can't get it.
+					// { "solutiondir",  proj.ParentSolution != null ? proj.ParentSolution.BaseDirectory : proj.BaseDirectory },
+					{ "targetpath",   Path.Combine (Path.GetDirectoryName (target), Path.GetFileName (target)) },
+					{ "targetdir",    Path.GetDirectoryName (target) },
+					{ "targetname",   Path.GetFileName (target) },
+					{ "targetext",    Path.GetExtension (target) },
+				};
+
+				for (int i = 0; i < extraArgs.Length; i++) {
+					var argument = extraArgs[i];
+
+					cmd.AppendTextUnquoted (StringParserService.Parse (argument, customTags));
+				}
+			}
+
 			return cmd.ToString ();
 		}
 
@@ -224,6 +264,7 @@ namespace Xamarin.MacDev.Tasks {
 			Log.LogTaskProperty ("CoreSources", CoreSources);
 			Log.LogTaskProperty ("DefineConstants", DefineConstants);
 			Log.LogTaskProperty ("EmitDebugInformation", EmitDebugInformation);
+			Log.LogTaskProperty ("ExtraArgs", ExtraArgs);
 			Log.LogTaskProperty ("GeneratedSourcesDir", GeneratedSourcesDir);
 			Log.LogTaskProperty ("GeneratedSourcesFileList", GeneratedSourcesFileList);
 			Log.LogTaskProperty ("Namespace", Namespace);
@@ -231,6 +272,7 @@ namespace Xamarin.MacDev.Tasks {
 			Log.LogTaskProperty ("NoStdLib", NoStdLib);
 			Log.LogTaskProperty ("OutputAssembly", OutputAssembly);
 			Log.LogTaskProperty ("ProcessEnums", ProcessEnums);
+			Log.LogTaskProperty ("ProjectDir", ProjectDir);
 			Log.LogTaskProperty ("References", References);
 			Log.LogTaskProperty ("Resources", Resources);
 			Log.LogTaskProperty ("Sources", Sources);
diff --git a/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.ObjCBinding.CSharp.targets b/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.ObjCBinding.CSharp.targets
index 7aa35b4b22..7a7aeeec28 100644
--- a/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.ObjCBinding.CSharp.targets
+++ b/msbuild/Xamarin.iOS.Tasks.Core/Xamarin.iOS.ObjCBinding.CSharp.targets
@@ -68,13 +68,15 @@ Copyright (C) 2013-2016 Xamarin Inc. All rights reserved.
 			CompilerPath="$(CscPath)"
 			CoreSources="@(ObjcBindingCoreSource)"
 			DefineConstants="$(DefineConstants)"
-			EmitDebugInformation="$(BTouchEmitDebugInformation)"                             	
+			EmitDebugInformation="$(BTouchEmitDebugInformation)"
+			ExtraArgs="$(BTouchExtraArgs)"
 			GeneratedSourcesDir="$(GeneratedSourcesDir)"
 			GeneratedSourcesFileList="$(_GeneratedSourcesFileList)"
 			Namespace="$(Namespace)"
 			NoStdLib="$(NoStdLib)"
 			OutputAssembly="$(OutputAssembly)"
 			ProcessEnums="$(ProcessEnums)"
+			ProjectDir="$(MSBuildProjectDirectory)"
 			References="@(ReferencePath);@(BTouchReferencePath)"
 			TargetFrameworkIdentifier="$(TargetFrameworkIdentifier)"
 			BTouchToolPath="$(BTouchToolPath)"