Trying to make SpiraTest work with medical devices

I am new to SpiraTest and have almost figured out how to make SpiraTest work within 21 CFR Part 11 (medical devices).  I have a few remaining questions I'm hoping someone may have good pointers on:

We have User-Needs which get Validated.  Each User Need consists of one of more Requirements which get Verified.  My plan is to just "indent" the Requirements and leave the User Needs as top-level "requirements".

My concern is that when all requirements are tested, the tool will show the User Need (top level) as having been tested.  But I want to require a separate "Validation" for all top-level User-Needs.   

Any suggestions on how to implement this?

Second and last question: Looking for best practices on versioning test case protocols.  I can add a custom "version" field to the test case and require a signature to "release" it.  If I then want to edit it, I was thinking of cloning the test case, resetting the status to "not approved" (or whatever), and incrementing the version number.   Anyone have experience with this workflow and potential pitfalls?  This would result in one requirement being tested by multiple test cases (different version number)... I think that's ok.

Appreciate any feedback.

Thanks

-Ed

Each USER NEED gets translated into several REQUIREMENTS (SRS for Software and REQs for Hardware).  REQUIREMENTS get Verified.  USER NEEDS get Validated.    I was going to put all User Needs as the top level Requirements, and the Requirements would be "indented".  My concern is that if all requirements are tested, it will show the User Need as having been tested.

1) I will add a required signature to release a Requirement. Great.  Now I want to release "Version 2" of the requirements in our document control system so I will have SpiraTest output a list of requirements in PDF format so check-in.  In the check-in process (we use Arena), we always need to say: "What changed since the last approved version".  Is there a way I can filter requirement based on when they were edited? As in:  Show me all requirements which were edited since I released the first version?