Here's another one, but I haven't tried it. But it looks promising and very detailed.

Information. http://forum.avsim.net/topic/313012-tcas-and-traffic-display-gauge-v20/
Download. http://library.avsim.net/search.php?SearchTerm=TCAS+and+Traffic+Display+Gauge+V2.0&CatID=root&Go=Search
There's a pdf included in the TCAS DOC V2 folder which explains the installation quite good, so you should get your popup easily.

Traffic usually avoids me ('oh my god, CoolP is on the yoke!!!!'), so I don't run into needing any TCAS.  8-)