'Umläute' disappear when creating PDFs

Hi All

In English - sorry replies in German are ok. I can read it but not write it.

OS MAC Leopard 10.5.2
Ragtime 5.6.6
Distiller Professional 8.0.0

We have the problem that 'umläute' are not being printed. by this I mean just the two dots on the top of the letter!
This always happens in tables and sometimes in block text.

Problem occurs when I generate a PDF using the print function to create a PS file that is then distilled.

Problem does not occur when the PDF is generated by exporting out of RagTime direct to Distiller.

We have tried changing row height in tables and differing fonts (our standard font is helvetica).

i have looked through the forum with no success.

Any ideas would be welcome.