My notes for Lacerte, which works similarly, say:
Can't be handled in K-1 input screen. Have to set up as Sch D entry and back out of K-1. We get 1202 treatment only if we owned the partnership at the time it invested in the QSBS, and the partnership held it 5 years. We bought this Date1. No 1202 treatment prior to Date2! For Date3 all the 1202 stock gets better treatment. Post 9/27/2010 amounts get 100% exclusion. Reduce K-1 LTCG, increase TE income or make an entry in Other Increases to Basis.