sorry the last one was from memory, in arma 2 use this code
_missile = nearestObject [player,"B_556x45_Ball"]
_pos = getpos _missile
_ckn = group m1 createunit ["cock",_pos,[],0,"NONE"]
_ckn setpos getpos _missile
_ckn setvelocity velocity _missile
deletevehicle _missile
#bam
_npos =getpos _ckn
~.2
_bam = "Sh_125_HE" createvehicle _npos
_bam setvelocity velocity _ckn
_npos = getpos _ckn
~.2
_bam setpos _npos
_bam setvelocity velocity _ckn
~.6
deletevehicle _ckn
exit
I tested it it works. you need to place a unit on the map named m1