Promblem with the custom install combobox

I have this snippet in my install code :

!ifndef NOINSTTYPES
InstType "Minima"
InstType "Completa"
InstType "Personalizada"
!endif
But the personalizada item appears twice in the combobox, why this happend? ,Anhoter question how i tell the program that select one checkbox or another when i select the installation type in the combobox?

Thanks
In advanced...

i guess "personalizada" is the default translation of the "custom" installtype, which is always there