How to manage installments and mortgage for customers?

I’ve been testing Dolibarr out for some time and I really love all the features and the flexibility it comes with. However, one thing it seems to lack and, I couldn’t find anything in the documentations and forums about, is managing products/services sold as mortgage or with installments (with an advance payment at first and a number of installments (like say 6) each at a set interval). We have a number of services that are costly and a few of our loyal customers normally purchase them on this installment basis. And we would like to monitor the dues, grace times, etc…
Is there anything that can help? If no, is there any work around?