Mortgages?

[Dan Kegel]

I'm starting out trying to use gnucash, and am creating
my table of accounts.

How should mortgages and mortage payments be represented?  

I expect a mortage payment will be a transaction that
debits my checking account and credits a liability account called 'mortgage'.

What should the initial balance of 'mortgage' be? 
-1 * the sum of all future payments?  Then it would nicely
zero out once I make the last payment.

Or should it be -1 times the principal owed?  

Or should there be two accounts - 'mortgage interest' and 'mortgage principal'?
And must I manually split each payment?

Egads.

- Dan