Hey Carlos,
I have implemented a C service that calls C functions in a DLL. If you use Developer to create a C service, it will create a stub C program in \webMethods6\IntegrationServer\packages<package_name>\code\source. Follow the instructions in the C program to create impl.c. You can add your code to the C program and compile it locally where you have access to a C compiler, then copy the objects back to the server.
Hope this helps.
Andy
#Integration-Server-and-ESB#webMethods#webMethods-General