Employee locking issue

Dear Experts,

I am trying to update infotype 0003 using BDC Call transaction method. Before calling BDC, i am using funtion modules to lock the employee. The employee gets successfully locked by the FM and when the program calls the PA30 screen to update the employee, it throws an error "Person is already being processed by user XXXXX".

I know that BDC internally sets a lock on the employee but i have a requirement to explicitly lock the employee.

Any pointers on this is highly appreciated.

Thanks in advance.

Murthy