Selling personal property in Ukraine.

Dear ALL,

Please answer my question or direct me to the right source.

I have a property in Ukraine that I owed for 10 years. Finally I decided to sell it and I have a buyer who leaves in Canada and going to buy property for personal usage. To make payment secure, he will do money transfer directly from Canada to my account in US. He wants to do it this year (to get tax relive probably), but we will do the final paperwork next year when I will be able to go to Ukraine. I know for sure that I should pay sales TAX in Ukraine, but:

Question: I don’t know if I should pay ( and how much) taxes in US. Already spoke with my tax adviser - he doesn’t know either. He advised me to leave 20% of money just in case if IRS will ask question.

Is any one on this Forum was in this situation?