Tax Reporting

I live in the state of Washington in the USA.  We have to charge taxes based on about 750 different local cities/areas based on the shipping address.  The good news is washington provides c# code to calculate this.  So I created my own Tax Provider and I'm pretty close to having the right amount of tax work.  

The problem is that usually on a quarterly basis we have to pay the taxes to the state.  On the tax filing form I have to indicate how much tax I collected for each of the 750 areas in the state that I had a financial transaction for.  There is a tax code # that is associated with each area and I would like to:
a) save the tax code with the order somehow, and
b) run a report that would list how much tax I paid for each tax code #

Is there someway to do this today?  Adding data fields seems pretty daunting.

   -Matt

Well, I found this about adding data fields:

http://blogs.planetcloud.co.uk/mygreatdiscovery/post/How-to-extend-nopCommerce.aspx

but I would like to know if there isn't something already built in that will allow me to do this in an easier fashion.

   -Matt

Got that done for my site!

Also added an option for USPS Insurance.