LSMW SEL_DATE filed Single - Character Flag

Dear gurus

i created a lsmw for T/code VK12 . I faced problem when the LSMW read till convert data.

In the VK12 , this Screen Field SEL_DATE will be my valid on date. I created the source filed Valid on date to match the mapping with SEL_DATE.

Here are my example of data:

SEL_DATE : 12022009

VALID_ON : 12022009 ( read from my text file)

the recording , mappings and source fields are created perfectly. Even read data display , the record able to shows out accordingly. But when comes to convert data , SEL_DATE return to me 1 Field Length.

Now i feel so puzzled, why this happen?

After some checking find out that this particular field SEL_DATE is a "SINGLE-CHARACTER FLAG"

expert out there, do you have any suggestions or guidance? i really need this field as to identify my record.

Without valid on date i can't call out the specific record and update it using LSMW

thanks

Wilson Low