Disk usage and bandwidth overage billing with cPanel

Hi,

I'm looking to setup disk usage and bandwidth overage billing with cPanel integration and have a few questions about the best watt to set this up.

Lets assume our package has 100mb of disk space and 100mb of bandwidth and we want to bill per mb for any usage over this.

In WHMCS I can setup a package with the 100mb limits and turn on overage billing, I believe I'm pretty clear on this side of things. I'm not sure how to set things up in cPanel though...

If I setup an account with a 100mb disk quota then the account will not function correctly when this quota has been reached and the user will be prevented from using any more space. However if I was to setup an account with 500mb of disk quota then the user would be shown that their account has 500mb of available space when the login to cPanel, this would no doubt be very confusing for customers and they would end up disputing their bills for using over 100mb in a month. Is there a way to setup cPanel so the user can be shown the correct "soft" limit for their account while also being allowed to go over the limit without any problems on their account?

Regarding bandwidth I believe I can set "Bandwidth limit check" to off in tweak settings and this would allow all accounts to go over their limit without any issue. When this setting is off are the bandwidth usage warning emails still sent out according to the limit set on the package e.g. 100mb or will no notifications be sent out because all accounts are effectively set to unlimited?

Maybe there is a better way to set this up?

Thanks

Jamie