Customizing expense charts

[JBW]

I'm trying to make my "Income/Expense" and "Expenses Over Time" charts 
make sense. At the moment they are not meaningful as loan repayments 
(which under accounting rules cannot be registered as an expense) do not 
show up in these reports. However loan repayments form a significant 
part of my monthly cash flow.
How can I generate charts that show ALL monies (whether expenses or not) 
flowing in and out of my Asset:Savings Account?