We returned from the States, and got approved for a <50% LTV mortgage on the basis of our savings record (had to show 6 months US bank records). I too was self employed, and showed copies of my tax records for previous two years. I did self-assessment through a computer tax program, i.e. there was no accountant, and hence no-one to sign off on my tax compliancy, which seemed to be a bit of a problem, but the bank accepted this on the grounds that this is the way in the US. It was a nervous time getting all the documents together, but the bank were willing to substitute "foreign" forms for the more usual Irish forms.
Good luck
-DeliaQuad