Hi Mike
Yes you are right at everything mentioned above. Check my other post as well.
DDLB field is added trough AET - > this tool will enhance all the structures for us. check the video link I posted.
You can add fixed values at your domain level by using a Z domain instead of the standard domains for your field. That would give you a ddlb automatically.
If that is the case store them temporarily into a structure/itab in set method and use them further. but what happens when the product is re opened next time, you don't need to retrieve the values back?
Regards
Vinod