lookup with key field


I have a simple table with a key and a description e.g.
col_id       colour
1                 "red"
2                 "blue"
3                 "green"
and a second table with a text field an integer field (which will hold the key value for this record)
item_name   col_id
"grass"               3
"sky"                    2
"tomatoes"        1
I want to show the second table in a grid with the colour not the number
col1                col2
"grass"          "green"
"sky"               "blue"
"tomatoes"    "red"
BUT I want to use a drop-down editor to change the colour in col2 on the grid.
I can get the DBAdvGrid to display the colour by putting a lookup field in the CDS but the drop-down editor gives an itemIndex=-1 error because it is trying to write back to that field.
If I display the number in col2 the drop-down editor works fine - it displays the colour in the combo box and updates the number in the grid.
Using HTML in the col2 almost worked in that <#colour> displayed the name with the field = col_id BUT this caused the drop-down editor to stop appearing.
Surely this is possible?

ignore that - it appears all the convoluted stuff I read in the demos/ doc is unnecessary

unless it all crashes around my ears during testing it appears that a lookup field in the underlying CDS with 'uselookupeditor' ticked just works!!