F4 help question

I have ztable with fields field1 and field2.

I want a f4 help to set up on field 1 with more then 10 char..

eg..if I do a f4 help on field1 I want to get the pop with /zdatadictiionaly/field1234 and /zdatadictionay/field12342.

I tried to do pu the fixed value with in the values range with in domain but this only enbles 10 char in it.

any clue of how to do ?

Thanks,