Best place to store e-mail?

Hi

I'm looking for advise on a a correspondence log I wish to
create using both Outlook and Access. My current thinking
is to use Access to assign a unique identifying number to
the messages, but keeping the majority of the information
store as fields in the e-mail message.

The correspondence log needs to be accessed by multiple
users, and so I need to decide where I'm going to store
the e-mails. The problem is that I am part of a
subcontracting group on a large project, and am working on
another companies computer network. A special request to
the client would be required in order for a public folder
to be created on their network for our use (if they allow
it).

My thoughts to an alternatives of a public folder are to
save the e-mail messages individually to the file server,
or to use a .pst file to save them on the server.

Can someone please advise me on the pros and cons of my
alternatives to NOT storing e-mail in a public folder?

Thanks

Lachlan