change from comma separation to dot separation in iis 7

Hi

We do have a small program that is called via a webservice in IIS 7. That program reads some information from file but IIS 7 i set op to use comma separation instead of dot separation  so the information is read wrongly. 

When calling the program outside our webservice it is reading our files correcly.

My question is: where do I change our IIS 7 settings to it uses do separation instead of comma seperation?