Hello,
There has been a while since you post this thread. Have you managed to locate a solution or workaround? If yes, would you please share it here, it would be helpful for others.
Do you mean you want to have one business role, say Z_SALESPRO, after logon, there will be a page for end user to select the enhancement set to be used?
But the enhancement set will be loaded at the initial step when we determined the business role.
Maybe you can look into the implementation of component_loading in se18/se19, if there is chance to introduce a user decision instead of just read it from enhancement set + client customizing table.
Hongyan