put space to a field of char type

hi,all:

my difficult is that when i call a FM through RFC,the FM have a requried field(type is char),but our system can not be able to offer,so i wanna put a space or ' ' to this filed,cos the FM will check that if the field is 'initial'.can anyone tell me how to put a space to a char type

field,thxs in advance.

best regards,

kevin