Upgrade Single Package Question

Hi,

I'm new to WHM/cPanel and struggling a little. I have the option to go onto plesk but trying to make WHM work for me, maybe one of you gurus can help me out

We sell limited packages where a customer may want to upgrade disk quotas. Once a package is assigned to a customer say 10GB for 10 email addresses. Is there anyway we can upgrade that package just for that customer to have say another 1GB, we want it as an extra and using the built in upgrade just replaces the package completely. Doing this may work but we will end up with many packages and its messy. Plesk allows addons to be assigned seperately, much easier.

Secondly - why cant we set email quota limits? Am i missing something here... we sell email only packages with limits on mailboxes and options to extend the size of the mailbox by X amount. Is there anyway to restrict a email box via WHM, not cPanel. Seems to be very popular but little trivial things like the above missing. Apologies if i am being naive here.

Thanks alot

 

Thanks for the replies Michael, i will do this.