I've been struggling to come up with a solution for early production cars to shift straight out of D.
For pre-LCI paddles (applies to both SSG and DCT), obviously the paddles just short their 2 wires (or 2 pairs with common center in case of SSG). But when these 'shorts' are sent through the MF button circuits, they come out as 1k for upshifts and 0.33k for downshifts at the steering column (resistance between the 2 wires; maybe I should have measured true resistance of each...)
These 2 wires (terminals 2 and 4 on the clock spring connector) are then sent to terminals 35 and 52 in the junction box. This is where it gets interesting--junction box has different circuitry based on production date, changing at 03/07 and then again at 09/07. 03/07 production just about corresponds to the proven production cutoff for D-shifting ability.
I bought an 05/08 prod. junction box for cheap to see if it could finally work but have yet to code it, car seems to work with it installed however. I think that maybe with the proper VO option $2XA added to the newer-production junction box it could work...