Trouble rewiring ableton as master to pro tools 12

[CJVD22]

So I just bought pro tolls 12 and I'm trying to rewire it as a slave to live. From what I've read I should be able to open live first, then pro tools and be able to route the incoming tracks into ableton.. But when I open the I/O for abletons tracks I see no options for the tracks I have in pro tools. One thing I noticed is I can't use the same playback engine in both daws... I can choose my Steinberg ur12 in one or the other but not both, is that where the issue is stemming from? Any advice is appreciated!

[doghouse]

Pro Tools cannot be a Rewire slave, only a Rewire master. You must slave Live to Pro Tools. The audio interface should be connected to Pro Tools and the audio from Live will be routed through Pro Tools.

Live is the only DAW I know of that can be master or slave.