The problem is that Trixx don`t recognize 2nd card, just working with 1st.
Would this work to
trick the trixx:
1. set clocks to the first card as usual
2. switch your primary display to 2nd card, so trixx treats your 2nd card as 1st display.
3. set clocks to the 2nd card(which is now hopefully detected by trixx as your 1st)