Lookups on UDFs

Question

We have added some UDFs to Business One (2005 SP01) which we have supporting UDTs for, and the UDFs are used on Document Lines for various document types including POs and AP Invoices.
We would like to provide lookups and validations on these UDFs.  One complication is that the list of valid values is conditional on other values on the line, and so may be different from line to line.
One option is combo boxes which would be tidy, but there seems to be no way to change the UDFs to be combo box type fields.
The other option is to create a ChooseFromList object.  Is there a good code sample available that illustrates the techniques involved:
- creating a Choose From List on a UDF
- populating it based on particular conditions
- return the selected vale to the originating control
We would be grateful for any help on this.

Answer 1

- validations on UDF: you can add valid values or you can
do this from UI by catching the VALIDATE event and attach
your validation logic to this event. ComboBox looks the
cleanest way of doing it, you could visualize your UDFs
as combos too
- CFL: there is documentation on the e-learning material
available here on SDN and samples too available