Downpayment, Partnerships Commercial RE

[Matthew Arnold]

Hello:

I run a small business in Boulder and want to move our company to a building we own. Our commercial banker is willing to do a loan at a good rate up to 75% LTV. The only problem: I don't have the 25% downpayment. I know there are a number of creative ways to come with the downpayment, but my questions are related to structuring a deal with a private money partner:

Hypothetical: I want to make an offer on a commercial building valued at $500K. I have a money partner who contributes the 25% downpayment but my small business covers all mortgage payments and operating expenses. 

What should I offer the money partner? What does a 'standard' deal or partnership agreement look like in the above scenario? 

Any guidance you can provide would be much appreciated.

~Matthew