Structure of a deal

[Abraham Kauffman]

im playing with using a structure for purchasing commercial or commercial with rental units that involves an investor putting up the down payment and my side holding the mortgage. The investor would get 30% net, rest paid 50/50 until the down payment is repaid then 50/50 thereafter. 

My biggest question is if there should be some sort of fee for essentially doing the foot work, finding the property and going through all the steps given the down payment is being paid back. I was playing with 2% of purchase cost of the building. The amount would be a part of the total cost of the building, not charged to the other party