diff --git a/extensions/transformiix/source/base/txURIUtils.cpp b/extensions/transformiix/source/base/txURIUtils.cpp
index 912215d37980..81eeea6b9ab7 100644
--- a/extensions/transformiix/source/base/txURIUtils.cpp
+++ b/extensions/transformiix/source/base/txURIUtils.cpp
@@ -349,6 +349,10 @@ URIUtils::ResetWithSource(nsIDocument *aNewDoc, nsIDOMNode *aSourceNode)
     aNewDoc->Reset(channel, loadGroup);
     aNewDoc->SetBaseURL(sourceDoc->GetBaseURL());
 
+    // Copy charset
+    aNewDoc->SetDocumentCharacterSet(sourceDoc->GetDocumentCharacterSet());
+    aNewDoc->SetDocumentCharacterSetSource(
+          sourceDoc->GetDocumentCharacterSetSource());
 }
 
 #endif /* TX_EXE */
diff --git a/extensions/transformiix/source/xslt/txMozillaTextOutput.cpp b/extensions/transformiix/source/xslt/txMozillaTextOutput.cpp
index 8e3780aaa8cd..d02cf99753cf 100644
--- a/extensions/transformiix/source/xslt/txMozillaTextOutput.cpp
+++ b/extensions/transformiix/source/xslt/txMozillaTextOutput.cpp
@@ -48,6 +48,7 @@
 #include "nsIDocumentTransformer.h"
 #include "nsNetUtil.h"
 #include "nsIDOMNSDocument.h"
+#include "nsIParser.h"
 
 static NS_DEFINE_CID(kXMLDocumentCID, NS_XMLDOCUMENT_CID);
 
@@ -182,6 +183,18 @@ void txMozillaTextOutput::createResultDocument(nsIDOMDocument* aSourceDocument,
     doc->Reset(channel, loadGroup);
     doc->SetBaseURL(sourceDoc->GetBaseURL());
 
+    // Set the charset
+    if (!mOutputFormat.mEncoding.IsEmpty()) {
+        doc->SetDocumentCharacterSet(
+            NS_LossyConvertUTF16toASCII(mOutputFormat.mEncoding));
+        doc->SetDocumentCharacterSetSource(kCharsetFromOtherComponent);
+    }
+    else {
+        doc->SetDocumentCharacterSet(sourceDoc->GetDocumentCharacterSet());
+        doc->SetDocumentCharacterSetSource(
+            sourceDoc->GetDocumentCharacterSetSource());
+    }
+
     // Notify the contentsink that the document is created
     nsCOMPtr<nsITransformObserver> observer = do_QueryReferent(mObserver);
     if (observer) {
diff --git a/extensions/transformiix/source/xslt/txMozillaXMLOutput.cpp b/extensions/transformiix/source/xslt/txMozillaXMLOutput.cpp
index f13438992d8a..4474955c8a26 100644
--- a/extensions/transformiix/source/xslt/txMozillaXMLOutput.cpp
+++ b/extensions/transformiix/source/xslt/txMozillaXMLOutput.cpp
@@ -725,6 +725,13 @@ txMozillaXMLOutput::createResultDocument(const nsAString& aName, PRInt32 aNsID,
     // Reset and set up the document
     URIUtils::ResetWithSource(doc, aSourceDocument);
 
+    // Set the charset
+    if (!mOutputFormat.mEncoding.IsEmpty()) {
+        doc->SetDocumentCharacterSet(
+            NS_LossyConvertUTF16toASCII(mOutputFormat.mEncoding));
+        doc->SetDocumentCharacterSetSource(kCharsetFromOtherComponent);
+    }
+
     // Set the mime-type
     if (!mOutputFormat.mMediaType.IsEmpty()) {
         doc->SetContentType(mOutputFormat.mMediaType);