Submit paid subscription as donation via paypal?

[BlizzardHQ]

I would like to use the paid subs in vB for our members to submit donations for our game servers. How can I change it though to link to paypal as a donation instead of a subscription.

Because this is a WoW private server, we can not sell anything. We can only accept donations and give the player a in-game gift based on donation amount. So because of this accepting payments or subscriptions is not an option.