On the "Values" properties box of the combobox control, add a "Formula Item". The formula you write should return an array of strings. Every string in the array can have a label and value if you add a pipe (|) character to it, e.g.:

 

[
  "label1|value1",
 "label2|value2"
]

 

In the pre-XPages era, this syntax was also used to add values to a combobox on a Form.

 

Mark