I managed to integrate the freeware TCAS II gauge from flightsim.com (search: TCAS II gauge)

Remember to back up your 727 panel.cfg before changing anything.

Follow the steps in the TCAS II folder for installation.

Here is the section from the panel.cfg - just copy over the sections changed here in the panel config.

[Window02]
size_mm=349,845
position=8
background_color=25,0,0
visible=0
windowsize_ratio=0.75
ident=RADIO_STACK_PANEL
gauge00=Captain_Sim.p721.P10!P10_001_vhf,  0,  0,349,190
gauge01=Captain_Sim.p721.P11!P11_001_vhf,  0,190,349,190
gauge02=ILH_TCAS!Transponder, 0,380,349,155
gauge03=Captain_Sim.p721.P01!P01_001_adf,  0,535,349,155
gauge04=Captain_Sim.p721.P07!P07_001_adf,  0,690,349,155

And in [VCockpit01] replace line 07 with:

gauge07=ILH_TCAS!IVSI, 16,520, 219, 222
//gauge07=Captain_Sim.p721.L11!L11_vsi, 20,524, 217,220

and add this to the end of [VCockpit01] you know what to do with xx

gaugexx=ILH_TCAS!Logic, 0, 0, 1, 1, trafficinfo:yes volume:-100

If you use FSUIPC there is no need for the last part: trafficinfo:yes

Also for the F/O side [VCockpit07]

EDIT

gauge05=ILH_TCAS!IVSI, 12, 516, 219, 222
//gauge05=Captain_Sim.p721.R11!R11_vsi, 20,524, 217,220

http://i1117.photobucket.com/albums/k586/CNmodeler/TCASII_zps0acc64be.png

Thanks too Lee Hetherington for his TCAS gauge.

Enjoy!  ;)