diff --git a/Core/Makefile b/Core/Makefile
index 51a4d6f..4c71572 100644
Binary files a/Core/Makefile and b/Core/Makefile differ
diff --git a/IDT.js b/IDT.js
index d4851a2..65f82bc 100644
--- a/IDT.js
+++ b/IDT.js
@@ -93,7 +93,7 @@ function IDT(path)
 		// Parse meta info
 		var line = parseRow(dat.ReadText(adReadLine).split("\t")), i = 0;
 		this.codepage = parseInt(line[i], 10);
-		if (isNaN(this.codepage)) this.codepage = 1252; else i++;
+		if (isNaN(this.codepage)) this.codepage = 0; else i++;
 		this.table = line[i++];
 		this.key = line.slice(i);
 		for (var i in this.key) {
@@ -315,8 +315,8 @@ IDT.prototype.save = function(path)
 		dat.WriteText(buildRow(this.columns).join("\t"), adWriteLine);
 		dat.WriteText(buildRow(this.types  ).join("\t"), adWriteLine);
 		var meta = new Array();
-		if (WScript.Arguments.Named.Exists("CP"))
-			meta.push(WScript.Arguments.Named("CP"));
+		if ("codepage" in this)
+			meta.push(this.codepage.toString(10));
 		meta.push(this.table);
 		for (var key in this.key)
 			meta.push(this.columns[this.key[key]]);
diff --git a/MSI.wsf b/MSI.wsf
index 5344f8c..4c2c8ac 100644
--- a/MSI.wsf
+++ b/MSI.wsf
@@ -568,7 +568,7 @@
 			<description>Translate IDT file.</description>
 			<unnamed name="&lt;destination.idt&gt;" helpstring="Translated IDT file" required="true"/>
 			<unnamed name="&lt;source.idt&gt;" helpstring="Original IDT file" required="true"/>
-			<unnamed name="&lt;catalogue.po&gt;" helpstring="PO catalog file with translations" required="true"/>
+			<unnamed name="&lt;catalogue.po&gt;" helpstring="PO catalog file with translations" required="false"/>
 			<named name="CP" helpstring="Output code page" type="string" required="false"/>
 		</runtime>
 		<reference object="ADODB.Stream"/>
@@ -577,7 +577,7 @@
 		<script language="JScript" src="PO.js"/>
 		<script language="JScript" src="String.js"/>
 		<script language="JScript"><![CDATA[
-			if (WScript.Arguments.Unnamed.Length < 3) {
+			if (WScript.Arguments.Unnamed.Length < 2) {
 				WScript.Arguments.ShowUsage();
 				WScript.Quit(1);
 			}
@@ -587,16 +587,17 @@
 				idt_dst_path = WScript.Arguments.Unnamed(0);
 
 			try {
-				// Open and parse source IDT file and PO catalogue.
-				var
-					idt_src = new IDT(WScript.Arguments.Unnamed(1)),
-					po      = new POCatalog(WScript.Arguments.Unnamed(2));
+				// Open and parse source IDT file.
+				var idt_src = new IDT(WScript.Arguments.Unnamed(1));
 
-				// Translate records.
-				for (var key in idt_src.data) {
-					for (var col in idt_src.types) {
-						if (idt_src.isLocalizable(col) && idt_src.data[key][col] != "")
-							idt_src.data[key][col] = po.translate(idt_src.data[key][col]);
+				if (WScript.Arguments.Unnamed.Length >= 3) {
+					// Translate records.
+					var po = new POCatalog(WScript.Arguments.Unnamed(2));
+					for (var key in idt_src.data) {
+						for (var col in idt_src.types) {
+							if (idt_src.isLocalizable(col) && idt_src.data[key][col] != "")
+								idt_src.data[key][col] = po.translate(idt_src.data[key][col]);
+						}
 					}
 				}
 
diff --git a/String.js b/String.js
index b588c57..6444baa 100644
--- a/String.js
+++ b/String.js
@@ -143,21 +143,26 @@ function Time2Str(date)
 function CodePageToId(codepage)
 {
 	switch (codepage) {
-		case 932 : return "shift-jis";
-		case 936 : return "gb2312";
-		case 949 : return "euc-kr";
-		case 950 : return "big5";
-		case 874 :
-		case 1250:
-		case 1251:
-		case 1252:
-		case 1253:
-		case 1254:
-		case 1255:
-		case 1256:
-		case 1257:
-		case 1258: return "windows-" + codepage;
-		default  : throw new Error("Unsupported code page.");
+		case 0: {
+			var wsh = new ActiveXObject("WScript.Shell");
+			return CodePageToId(parseInt(wsh.RegRead("HKLM\\SYSTEM\\CurrentControlSet\\Control\\Nls\\CodePage\\ACP"), 10));
+		}
+		case 932  : return "shift-jis";
+		case 936  : return "gb2312";
+		case 949  : return "euc-kr";
+		case 950  : return "big5";
+		case 874  :
+		case 1250 :
+		case 1251 :
+		case 1252 :
+		case 1253 :
+		case 1254 :
+		case 1255 :
+		case 1256 :
+		case 1257 :
+		case 1258 : return "windows-" + codepage.toString(10);
+		case 65001: return "utf-8";
+		default   : throw new Error("Unsupported code page.");
 	}
 }
 
diff --git a/UI/Makefile b/UI/Makefile
index 100e9fc..f066cc5 100644
Binary files a/UI/Makefile and b/UI/Makefile differ