What's the recommend approach for generating URL's to child pages of a users profile page with query string params?

e.g. Profile page http://server/user-name/subpage/paramName/paramValue

I am trying to use this code (VB) from a profile sub page:

But this results in: http://server/user-name/ofuser/4/subpagename and the sub page name comes after my supplied params.

I should mention I am using masterUrl with this too.

Any Ideas?