Description tag form first x chars from first post

[ahmed19]

Hello. I have question about description tag in vbulletin. Can i take words to my topic description form first 300 chars of first post?

Exemple
meta keywords: Topic Title - keywords
meta description: Topic title - Subforum Title
...or something like that

I wont to take first X chars form first post in topic
Exemple
meta keywords: Topic Title - keywords
meta description: blablabla lalala blablabla

:)
Please help

[gfxhelp.com]

I'm looking for the same thing, if anyone knows about how this can be done it would be appreciated.