A few active_merchant questions

Just getting started using the active_merchant plugin and had a few
questions for those of you using it out there.

First off, I’m using the Trustcommerce payment gateway and they require
that you set a parameter named ‘avs’ to ‘y’ if you want the transaction
to perform an avs check first. How do I set this in the activemerchant
authorize method? There’s an options hash that it takes but after
looking at the source it doesnt seem to do anything for trustcommerce.

2nd question: I’m using the creditcard valid? method to do my form
validation, is there any option to get it to throw an error if
verification_code is invalid/blank in the form? or do I need to do it
manually in my own code? By default it doesn’t seem to care if its blank
or not.

3rd question: is there a preferred method of supplying the address
information for avs in active_merchant? I noticed a private add_address
method in the gateway code for trustcommerce but can’t figure out how to
use it properly.

Thanks so much for the help!