JV Development Deal - Structure/Fee?

[Sam Cho]

I'm a new commercial real estate agent and found the seller an interested JV partner to finance the construction and redevelop an office property to a multi-family building. They would make their investment back and split the equity 50-50. My question is three-fold:

1) Who pays the commission - the seller who hired me, or the JV partner who wants the development opportunity? What is it based on?

2) Does my broker get a piece even though this isn't a direct sale of the building? 

3) What should I negotiate?

Thanks everyone!