SSRS stored procedure as dataset with report parameters not working...

In my report i use 3 stored procedures. All of them are using parameters, and 2 of them work perfect and the third one is not, which i really do not understeand.

Stored procedure takes 2 parameters

       SPgetData @reportnr,@username

The parameter @username is also used by the 2 other SP's

If I call in dataset Query Text then it works, but then I have to specify the parameters by hand like :

    SPgetData '001','Administrator'

If I try to set Text to

   SPgetData @reportNr,@username it opens the screen to enter the valuesby hand..

This is really very strange as 2 other procedures work perfectly with exact the same setup (As Stored Procedure with reportParameters...

Is there a limit or something ? I use SSRS Express 2008 R2