Landlord Experience? Of course I have landlord experience.

I've lived with people under my roof and even had to kick them out, but the bank says without a lease agreement I can't use this as landlord experience on my mortgage application. 

What are some creative ways to get landlord experience so I can count rents on my mortgage?

And, how long do you have to be a landlord before you can put it on the application?

Let me know what you think!

Thanks