Problems with namespaces

I have problem with namespaces. I have a program that consumes the web service and has for instance names space nsProgram. In this program I have defined several classes that I use for storing and handling internal information. Than I have web service, that also uses the same classes (I included the file as linked external resource). I included this web service as web reference and used name wsWeb.

When I am trying to call the web service with parameter that is my class (for instance Data) I can declare this Data class in my main program without any problem, but compiler reports an error:
Error 1 The best overloaded method match for 'nsProgram.wsWeb.WebData.Test('nsProgram.wsWeb.Header)' has some invalid arguments
Error 2 Argument '1': cannot convert from 'nsProgram.Data' to 'nsProgram.wsWeb.Data'

Why is the wsWeb also included for all data types? How can I get around that?

Thank you

Simon

.