I think that there is a bug that the ASP Runner 4.1 Build 172 (at least I found from this release) does not save the key field selected for ADD operation. It seems that it happens when the field is a link/key field to other table and you want to show the field in the Add screen. Therefore, everytime if I want to display the key field in the add screen, I have to turn it on and rebuild the project.
And another bug is the default value for the key field. The system still uses getrequestform rather than session.