Splits,
Based on the below, I see no reason why you cannot take the foreign housing exclusion on top of your mortgage deduction:
http://www.irs.gov/businesses/article/0,,id=202079,00.htmlGenerally speaking, you just have to be careful that you do not 'double dip' on any income for which you will have taken other exclusions, credits or deductions (such as the foreign tax credit and foreign earned income exclusion).
Please be aware that the foreign housing exclusion in particular is an 'audit trigger' item on the part of the IRS. You need to ensure that it is valid and that it can be substantiated.
I agree with PP that the situation you describe is fairly complex and having expert advice on it is warranted (whether it is you or your company that pays for such advice).