If you want it to be undetected by your carrier, than you need to root/jailbreak.
This isn't about tricky hacks and such so you can bypass your contractual agreement. Just simply getting internet from your phone to your surface. Near all plans have a tethering quota by default. You click the hotspot button and you're done.
If this was about fobbing off your carrier, then heck, I'd just install backtrack or such and hack every router within reach and never have to worry about paying what I rightly owe. You can also use TPB and never have to pay for your copy of office or Windows but I've a small hunch this forum isnt about bypassing any legal agreements or obligations.