Need a way to alter the payment processor credentials via hook

Tim,

further to our brief IRC chat - I want to be able to alter the payment processor credentials via hook. In theory the use case 'could' involve changing class - although in my case it doesn't.

Basically donations go to a different account to other payments and the way they get there is by going to a different payment gateway (of the same type ie. eway with different credentials).

At the moment the $paymentProcessor->_processor is a protected param and there is no setter. There is a general getVar getter (I'm not a fan of that & would prefer to add a specific getter but not religious on it either).

So, do I add a setter? Or, given that conceivably the same requirement could involve 2 different processor classes do I pass the object to the hook by params & then replace it if I need the credentials (as I would have to if I was changing from IATS to Paypal)

Please advise & I'll implement

Thanks