Problem to send mails with "html" on Windows XP machines

When we generate a email message on Windows 7 with pdfcreator the email is coded with "html" - when we do the same on a Windows XP machine the mail is codes with "text".

Is it possibled to do avoid this behavior?

We want to get a "html" mail in Windows XP too.

Every machine has Office 2010 Professional on it and the mail system is Exchange 2013 CU2.

Thank you very much.

Markus Greiner