Base: How do others than the first fields in form?

Hi,

forgive my newbieness. I thought it was better to ask to ask here than 
on the general lists since Base is not officially out - and since it 
seems I'm not the only one who has problems setting his mind to 
database thinking.

I have an adress table, and I want to create a form with a list box 
for the selection of country names. There is another tabel with an 
automatic ID, country names, and the postage rates for a letter there. 
The postage should appear in the form when one of the defined 
countries is selected from the list box.

What happens is that the list box shows the first column of the second 
table only (which happens to be the ID number). How do I show the 
entry of the second column (country name) there and of the third 
(postage) in another field next to it?

Thanks in advance,

klaus