How to fix Crystal Report Thai language problem

I have develop web application and use Crystal Report.

The problem occur when i use Thai language.

Thai symbol cannot read and its replace with square symbol.

The result have no problem when use CrystalReportViewer on window application (figure 1).

But the problem occur on web site (figure 2), when开发者_如何学运维 user request a report, i send the report back with pdf file format.

figure 1: Expecated Result

figure 2: Problem Result

The code look like below.

rptExternalTransferReport rptH = new rptExternalTransferReport();
rptH.FileName = Server.MapPath("/Reports/rptExternalTransferReport.rpt");
rptH.Load();
rptH.SetDataSource([datatable]);
Stream stream = rptH.ExportToStream(CrystalDecisions.Shared.ExportFormatType.PortableDocFormat);
return File(stream, "application/pdf");   

How to fixed this problem.

Help me please.

Edit 17-May, 2011: Look like the problem is occur when i export to pdf file. Because i try use CrystalReportViewer, it have no problem. But when export to pdf, the problem occurred.

PS. Sorry for my english writing :)

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What font you are using?

Please try with "Arial Unicode".I believe the issue is with the fonts - not CR. In order for a font to fully support certain languages (Chinese, Korean, Thai, etc.) the font must support Unicode or be Unicode enabled.

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Did you try to install Thai language on your machine?