Loans

[JBW]

I'm trying to figure out how to handle my loans in GnuCash. I've read the
tutorial but the method described does not really suit me.
The main problem is that the tutorial says loan interest should be 
registered as an
Expense. This however is not the case with me. Interest charges and loan
repayments are two separate transactions of differing values. My Expense is
the loan repayment, not the loan interest charge.

For example, on the 10th April I want to move $500 from my Asset named
Bank Account to reduce my Liability named Mortgage Balance. But I
ALSO want this amount to show up as an Expense named Mortgage
Repayment. This little equation has three sides (Bank Account, Mortgage 
Balance
 & Mortgage Repayment), thus I am having trouble dealing with it.

Then on the 20th April I want the Liabilty named Mortgage Balance to
increase by $450 (Loan interest levied), but there is not really a
balancing account that I can see. The balance of this Liability just 
increases
when the Loan Interest is levied against my mortgage account. There is no
Expense involved.

Does Equity somehow play a part in handling the transactions in the way
I want?
How do I deal with these transactions in the way I want?