Query Active Directory from a non forest member computer

Hi,

When I'm quering a GC from with my domain account and from a computer that is domain member everythings works fine:

Dim mySearcher As DirectorySearcher = New DirectorySearcher()

Now I'd like to the same from a computer that is not a domain member. I have and domain account with userName and password and I've got the gc address as fqdn by quering: nslookup gc._msdcs.domain.com.

Is the approach to use the DirectoryEntry in the DirectorySearcher contructor the right approach?If so what do I need to specify as path?

Dim entry As New DirectoryEntry(path, userName, password)

Dim mySearcher As DirectorySearcher = New DirectorySearcher(entry)

Thanks for any advice

John

P.S.

I've searched all microsoft.com, but did not find a dedicated AD Developer forum. So I post my question here and ask you to guide me to a more appropriate place if there is one.