Tail Sting on Su-34

The SU-34 & SU-32FN have an extra long tail sting in between engine nozzles. It has been reported that it may be capable of housing a targetting and guidance radar for a rear-firing defensive(is there such a thing??) missile system.

What are its possible implications in a theatre of war?? and what is the current funding on the SU-32FN and SU-34 in the russian airforce??

many thanx

adonis