I did it on my Behold II and it works 100%.
I set USB mode to Samsung studio, USB debug mode doesn't matter.
I checked Vibrant has Samsung Kies on USB mode and I am sure you can tether over USB with Cradlepoint router this way.
Now here is a question: did anybody try that?
yeah, it works very well
Currently: MyTouch Slide (white)
Former: iPhone 3GS Black 32GB, HTC HD2, Sony Ericsson Equinox, HTC Touch Pro2, HTC Dash 3G, Sony Ericsson TM506, BlackBerry Storm (unlocked for TMO), Samsung Behold, T-Mobile G-1, Verizon XV6800, Verizon Samsung i760, T-Mobile Wing, T-Mobile Dash, BlackBerry Curve, BlackBerry Pearl, Nextel i860, Nextel i730, Nextel i95cl.