Export XML + XSL: invalid charater (Unicode 0xb)

Dear File Maker developpers,

I read some posts in the forums but I couldn't find a solution for my problem, so here it is : I need to export some records to an XML file. I used the FMPDSOResult grammar, because it suits better to my needs, and also a XSLT file to perform an XSLTransformation on my data, and get a well structured XML file. This works fine, but not always

Depending on the records I decide to export, I got the following dialog box "Invalid Character (Unicode 0xb)"

So, I guess the problem comes from the records where there must be some strange characters, which are not accepted by the export process, but they are not visible. How could I skip this characters?

Then, if I decide not to use the XSL for the export (only XML export) and proceed to the XSL transformation outside FMPro (XML Spy for instance) it works fine, whatever the records I select. Could somebody explain me why the XSL transformation works outside and not inside FMPro? Is there any encoding pb? (both export and XSL are encoded in UTF-8 )

FMPRO -> (export) -> XML -> (FMPRO XSL) -> Invalid Character

FMPRO -> (export) -> XML -> (XML Spy XSL) -> OK

Thank you very much for any remark or comment on this issue!

Johann