Problem in F-53

Dear all

in our company we using f-53 for payment then we assign check with payment in fch5

the problem that in f-53 there is assignment no field in bank data

we put the check no in this field also coz the bank reconciliation depend on this field (we using the manual bank reconciliation )

the real problem is the assignment no is a text field and i can be put any number in it even i chose the correct check no from fch5

is there any solve for assignment no field in f-53 or a link maybe between f-53 and fch5