How to use set_destination function in custom mode from guided mode to go specific destination

Hello Everyone, i have added one custom mode in ardupilot. in that custom mode drone should go to the destination which i give in the global frame as (lat, long, alt). so the problem for this is , when i use the set_destination function from guided mode, the function calculates the lat ,long, alt in x y z in cm ,store it in variable and set submode as POS. and return the function. that means when i am calling the set_destination fucntion from my custom mode , drone is not going to the destination just calculating values and returning the function. Actually when we use the set_destination function in guided mode , it calculates the lat,long,alt in cm and set submode as POS and return function. and when again the run function call again and again at that time the submode is POS so the pos_control_start function starts working by taking values calculated by set_destination function and drone goes to destination. so the problem is i can’t able to call the pos_control_run function again and again from my custom mode. so how to handle this problem. if any one knows please help me.
mode_arucoland.cpp (3.2 KB), this is cpp file of custom mode in which gotodestination function is used to go destination . in that i made runPosControl function to call pos_control_start ,because it was private. so please help me how can i handle this problem to go to particular destination in custom mode. i am using copter version 4.4.0 beta 5.

Update to ArduCopter 4.4.4-beta-1 and stop double posting.

Yess. i have updated to 4.4.4 beta-1 but the issue is same.