Web Portal Customization Problem

I am trying to activate portal for my customers. I have removed unnecessary links for me like projects, orders etc. from portal to keep it more clean. Due to nature of business, I want my customers to see QUOTATIONS, INVOICES and PAYMENTS. Right now quotations and invoices are working properly, but i could not find any way to reflect payments made on the portal. Is there any way to add payments on portal also? I was able to put it on left menu (modified the Appointment menu from portal settings), but could not find the correct route for payments.
Beside that is it possible to show accounting ledger of customer on portal as report?
Replies highly appreciated.