How to list a folder from a server in a different domain

I have two domains, A & B. Now, within the same domain, lets say A, I can list a directory/folder in serverA1 from serverA2, using the "dir \\serverA1\temp" command from the command prompt.

The problem is, how do I list the same folder from another server in a different domain (lets say serverB1), using the same "dir" command.

For your information, these two domains have a two-way trust relationships, and both Administrators belong in the others administrator group.

I need this help urgently, thanks.