I need to know how "fenced in" an email message is while it's in the PST file. In an upcoming police matter I have an email message that supports my version and I want to know the value of this email.
Its properties (sent/recieved/modified) points to a date 8 months ago and this is crucial to have a case. But how will it look in the eyes of the Police?

Can I have forged this by...
* ... edit the content of an old email message without changing the modified date
* ... alter the properties, making it look older than it really is



This WHILE it's in the PST file. (I've tried myself to pull it out and edit as an MSG file, but it still has a new modified date when pulled back in and read in Outlook.)

If it can be done in the PST file, don't tell me 'how'. I've asked this question on other forums without replies and start to wonder if people don't want to answer in case I'm the bad guy.
But I'm not interested in how to do it. What I want is a rough picture of the value of evidence... 'easy, 'hard' or 'impossible'... if it can be used or if I'm going to look stupid presenting it.