This is a very very complicated issue.  You shoud involve a lawyer in thye development of the annexure.

You should also discuss with your client the nature of the relationship. 

• Is this deal oriented towards long term work together or a one off job?
• Are you planning to recover your costs via a service contract or from the delivery of the system?
• Is the software already built or is it going to be built?
• If it is for a future development will you be billing time and materials or a fixed price for a finished product?
• What defines successful project delivery?  What defines unsuccessful delivery?  What is in the grey zone in between?
• Do you rely upon any subcontractor?
• Does you client have a history of successful project delivery?
• What are your objectives from working with this client?
• Do you want to charge for outcomes or activities?
• Do you want to commit to specific deliverables for a project ahead of time?

I haven't got any templates for you (anyone else?)

It's my view this is a very case by case type doc.

Given where you are you now need to consider a few more things; whatever you write down becomes something that can be used to sue, so you really want to be broad.

Some things you could include are

• a high level architecture diagram
• A list of deliverred system requirements, maybe broken into functional and non functional categories.