First, make sure the IRS rules do not require Form 3800 to be included for this particular client's return. If it is not required, complete the 8582CR wkt worksheet (Passive Activity Credit Worksheet).
On the 8582CR wkt worksheet, make sure to complete the Description, Type, and Form entries, as well as at least one of the amount entries. This carries over to Form 8582CR (Passive Activity Credit Limitations), which shows the amount allowed. The data is then carried back over to Form 8586, and then to Form 1040, without involving Form 3800.
This information applies to all years of the UltimateTax software.