set myixp [$ns node]
	set ixphost [$ns node]
	tb-set-hardware $myixp ixp-bveil
	tb-fix-node $myixp $ixphost
	tb-set-node-os $ixphost RHL-STD

This gives you a handle on the host node so you can treat it like a
normal testbed node, including setting the OSID.

There are associated assign_wrapper changes, but I won't check those
in till I get back from vacation; not enough people around this coming
week in case I screwed something up.