But you would only have to do that if you were sending it to yourself. When you forward it to someone else, there should be no problem.
If you want to archive text messages for your own use, there are better ways of doing it, in my opinion. If it's something you need to do a lot, I'm a big fan of PhoneView. Copying and pasting it into a note would be my suggestion for occasional use.
This is a whole lot of "hoops" to jump through just to send a text to an email address. Copy and pasting the text message segment(s) into an email as was suggested in the message string is much simpler and quicker. Shame on Apple for putting its customers through such an ordeal.
It originally didn't occurred to me that people were asking how to forward messages to themselves. It appears that Apple views it much the same way I do. No system is going to work the way everyone thinks it should. You can submit feedback to Apple here:
http://www.apple.com/feedback