Missouri Real Estate Tax Loss from Non-Resident

[Alice He]

I live New York and invest in Missouri rental properties. Every year, I've been filing Missouri Non-resident tax returns with no tax due because we've been at a loss each year. 

Not sure where to report each year's losses (or carry over losses) so when we actually sell or make money on the properties, we can have prior year losses offset it! 

Would appreciate any advice or recommendations of an MO accountant!