How to extract timestamp from $threadinfo[lastpost]?

[Aylwin]

I'd like to add a meta tag in the printthread template with the time stamp from the last post. I got this reply from Jack Bunce at the vBulletin.com forum:

Add your meta tag to this template:

*Admin CP -> Styles & Templates -> Style Manager -> ? ? -> Printable Thread Templates -> printthread*

The *$threadinfo[lastpost]* variable contains the timestamp of the last post. If you want it translated to a readable date for use in the templates then you need to add custom code (plugin or file hack). For help with this you should post on www.vbulletin.org.

This points me in the right direction. Could someone please help go further with this?

Thanks,
Aylwin