The documentation is incorrect, for VLF-ONE. There is currently no code assistant that generates a VLF-ONE snap in instance list.
A code assistant will be added at some point in the future.
There is however a shipped example of a snap in instance list, under Example Applications -> Advanced -> Snap In Instance List. (example DF_T41I1O)
Also, you might want to investigate what can be done with the standard instance lists before creating your own snap in one, because In VLF-ONE there are alot more options for using your own panels in instance lists.
If you check this section
http://docs.lansa.com/140/EN/LANSA048/i ... anager.htm
and look at the sub-sections:
Using VLF-ONE Instance List Browser VF_UM040O
Using VLF-ONE Instance List Browser VF_UM041O - Introduction
Using VLF-ONE Instance List Browser VF_UM041O - Advanced
Making your own VLF-ONE Instance List Browser
Adding Additional Columns to Instance Lists
In the shipped framework, See Resource Applications --> People for an example of a business object that uses snap in panels (example DF_T40PAO)