I had exactly the same problem as yours. What I did was doing exactly what they mentioned above, but I do not restart my phone after registry fix.
So after you change your registry, dont restart, just change to another homeskin, and it will be updated.
The small problem is that you cant get your phone to be restarted, u'll then have to do the registry fix again
Hope it works for u.
Listen, I have an MPX200 with the generic rom and Jmms installed, and I find the registry entry. The only thing is, when I change it, nothing happens on the <a href=http://smartphone.modaco.com/viewtopic.php?t=714>homescreen</a>, and if I reset the phone, it resets the registry value back to the Jmms default.