At the moment there is no way to do it. At least with LimeWire.
Except stopping all uploads, disconnecting from the net and letting him browse you.
But since that feature seems important to you, would you like to post it in our feature requests board?
http://www.gnutellaforums.com/featur...s-bug-reports/
Besides: You stumbled into the Phex Forum with your question, which also is a Gnutella p2p Program, but isn't LimeWire.
Maybe that had a reason, and you should
give Phex a try...
Have a nice day