Investors & landlords

Okay, so in Turbotax how do you break up a sale such as this into two lots when it is reported as a single lot on a 1099?

For instance, I have a single sale which is reported on a 1099 as 100% long-term, but due to the unifying bases of partnerships rule 90% is LT and 10% is ST, so I have to create a ST entry to the contrary of my 1099.  I don't see a way to add a sale within that 1099, while adding it outside the 1099 would mean I would have to remove a portion of the proceeds from the 1099, creating a mismatch in numbers for the IRS.

Thanks.