ACR MDT CLBS ABOVE ASSIGNED ALT WHEN A TCASII RA IS RECEIVED.

Narrative

INITIALLY WE WERE CLRED FROM 4000 FT TO 3000 FT THEN OUR CLRNC WAS CHANGED TO DSND AND MAINTAIN 2300 FT; HDG 360 DEGS. THE CTLR THEN BECAME AWARE THAT THE VFR TFC SHE WAS WORKING WAS BELOW US AND IN FRONT OF US. THE CTLR THEN GAVE THE VFR ACFT A 140 DEG HDG AND TOLD US TO STOP DSCNT AT 3000 FT. WE WERE JUST GOING THROUGH ABOUT 3050 FT AT 1000-1200 FPM. WE STOPPED DSCNT AT 3000 FT AND THE VFR TFC CAME UP ON TCASII AS CAUTIONARY TFC AT APPROX 3.5 TO 4.0 MI AND 400 FT BELOW US. IN A COUPLE OF SECONDS AN RA FOLLOWED. WE CLBED AT 1500 FPM TO 3500 FT THEN STARTED OUR DSCNT BACK TO 3000 FT. WE ADVISED ATC ASAP OF OUR RA (THERE WAS A SHORT DELAY DUE TO FREQ CONGESTION; APPROX 7 OR 8 SECONDS). THE CTLR WAS UPSET ABOUT OUR RA. SHE WAS CONCERNED ABOUT OTHER IFR TFC AT 4000 FT TO THE W OF OUR POS (APPROX 5-6 MI). AFTER LNDG I RECEIVED A MESSAGE TO CALL THE ATC MGR. HE INFORMED ME THAT THERE WOULD BE AN INVESTIGATION OF THIS MATTER. IT SEEMED OBVIOUS TO ME THAT ATC IN FNT KNEW LITTLE OF TCASII; AND DID NOT LIKE OUR RESPONSE TO THE TCASII. IT IS MANDATORY THAT WE COMPLY WITH ALL RA'S.