An LSMW for Classification with multiple entries possible in the characte

Hello, we've got a LSMW which works fine on a recording using transaction CLMM. This updates characteristics data ok as long as the fields are single value entires (eg "Y" or "N" or "")

But now I want to add a new characteristic which can store multiple values eg Machine Type = "C10" or Machine Type = "C10, C18" or Machine Type = "C10, T01, T02, C30"

When I try to adapt CLMM it gives me an error that the format of the field is not correct. I tried comma separated eg "C10, T01, T02, C30" but it was not accepted.

Is there a special format for changing the multiple value characteristics in CLMM which I can use in LSMW?

Is there a more cunning way?

Do I have to get a development made for this??

Has anyone solved this problem?

Many thanks