ComboBox in VerticalLayout

I have form using
to display the contents of an
Oracle table
with one of the items being a key to a reference (Oracle) table.
Now instead of the key i want to
display the corresponding description
from the reference table
and as it should be possible to
create new entries
in the main table,
i need a
to display the possible values from the reference table.

I’d be glad to get a link to a comparable example app, to see if and how that might work…