Hi Buznee,
I managed to complete the mission after some attempts:
I have waited until SAM were taken out, then I killed the shilkas but let the bmps stay. I kept the wingman under control with the command "fulfill the mission" and "rejoin" and focused myself on the vehicles in the target box: vihkrs for the tanks and cannon for the soft targets. All that from stand off range (about 3 km) and from different positions (although sometimes I got missiles shot back... use flares!!). The mission is fulfilled when all the vehicles in the target box are destroyed.
The trip back home is also very "interesting": between the mountains in the night, especially when you forgot the to take with you the NVG... Anyway is very satisfacting when you land "the beast" at the FARP in the dark. I must admit that despite the difficulty I really enjoyed this mission, the ambiance is great
I hope it helps! Happy flying