How can I show specific fields in form's drop-down-list

Hi,

second attempt, hopefully without the kids rushing up before sending 
it off.

I have an address form with a list field for country names, and I want 
another field to show the postage for that country. Country names and 
groupings by postage plus an ID number are in a second table, and the 
actual postage for a given group in a third.

In the example of the "Getting Started ..." guide the relevant entry 
is simply before the ID and shows in the list field. In my case, the 
ID is in front and is the only thing that appears - not easy to choose 
a country from that.

I had suspected that a list field would (automatically) not show the 
ID, but some choosable relevant column, and I see more problems coming 
up for showing the postage amount instead of the postage group.

Hints welcome, and thank you,

klaus