While creating down payment request (t.code f-47), I specified 'F' in Trg.sp.g/l ind check 
box, the system thrown a message as, 
'Special G/L indicator F is not defined for down payment' 
Then I checked OBYR, there special GL indicator is available and I assigned GL accounts 
for postings, I have done the required configuration but where I missed, I could not find 
anyone have an idea to solve this issue,