Cisco – How to backup the configuration of a cisco switch and ASA to an SMB windows share

See this article for more information. I think you will need to modify your Network Policy to allow the use of PAP and SPAP. I haven't found a way to change the authentication protocol the ASA uses. Hope that helps.

You have quite a lot of options with the equipment you have. The main limitation right now seems to be your lack of familiarity with the ASA platform. If time is limited, then you should probably seek support/consulting from where the ASAs were obtained. If money is more critical than time, then you need to study up on ASA VPNs.

A good place to start is the Cisco Press ASA book (ISBN 978-1-58705-819-6) which has walkthroughs for setting up VPNs amongst other things, as well as explaining the concepts. The documentation available online is also essential reading, but it can be a bit hard to find exactly what you need.

You may also want to upgrade the firmware and ASDM on your ASAs. Version 7 is quite old now, and the more recent ASDM interfaces are a little better IMO. Also, if the Site B ASA is a more recent purchase, it is very likely it has a more recent firmware. You will find life easier if they are both on the same version.

When reading the documentation, it is essential you are reading the documentation that matches your firmware version - there are quite different configuration syntaxes between version 7.0 and the most recent version (8.4).