Set ApplicationName in code

Hello!

 In my webapplication I use multiple aspnet-applications. Roles and Membership works fine when I set it as in the code bellow, but when I try to update Profile properties it is creating a "/"-application and save a new user to this and ad all Profile stuff to this... Any suggestions how to set Profile.ApplicationName? 

DataRow dr = Site_getconfig(...);

 
Roles.ApplicationName = dr["ApplicationName"].ToString();
Membership.ApplicationName = dr["ApplicationName"].ToString(); ...