Interview multiple tax guys to find one that has an understanding of the IRA real estate rules. Ask "tell me the circumstances where UBIT would be due". Don't elaborate on what UBIT means, just use the acronym. If you get a blank state, they're not for you.
Not to derail the discussion, but the tax benefits of RE investing are way over stated. Realistically, the deductions will shelter the rental income. Good deals don't produce much, if any, passive loss. Crummy deals, like the ones you see on the MLS with the note "this cash flows!!!" do. Your ability to deduct this is very limited. Only if your AGI is under $100K, phased out completely at $150K. Limited to $25K so it only works for a few properties. The real kicker is you have to pay it back. When you sell a rental, the amount of gain up to the depreciation taken or that could have been taken if not taken is subject to "depreciation recapture tax", which currently maxes out at 25%. Recall also depreciation reduces the basis for your property, creating a correspondingly larger gain when you sell.
Passive losses are gravy you may get if you own rentals, they're hardly a reason to invest. I'll go further to say if your AGI is under $100K, and you have a rental that's generating big passive losses (i.e., its a crummy rental thats costing you money out of pocket), you really shouldn't be in the rental property business.
The best way to use IRA money for rentals is to pay all cash. But then if you realistically evaluate the expenses (see the 50% rule discussions in the rental property forum), you may find the return is too low for your liking. I do this calculation about every six months, hoping to see a way to make it work. It never does. Part of the power of real estate is leverage. By using debt, you get the gain for yourself. Even a small increase in rents or property value can give you a nice return. Without the leverage, it just doesn't give as good a return.
Personally, I find doing hard money loans with IRA money to be easier and more profitable. No issues of accidental contributions because you did work on your property (you cannot do any work yourself on a property your IRA owns because that would be considered a contribtution.) No UBIT issues because its an investments that's exempt from UBIT.