[TYPO3-english] Overwrite metatags with TS

[Bert Hiddink [BENDOO e-work solutions]]

Hello,

In order to overwrite metatags dynamically via TS, I noticed that the 
following works:

page.meta.description {
    data=DB:tt_content:5:uid
}

However, now I want combine this with a GP-var, fe:

page.meta.description {
    data=DB:tt_content:GP:my_uid:uid
}

page.meta.description {
    data=DB:tt_content:{GP:my_uid}:uid
}

Neither one of these works, what do I miss here?

Another option would be via a lib-object:

lib.test = TEXT
lib.test.value=my description

page.meta {
     description < lib.test
}

This does not work neither, do not see why. Any ideas?

Thanks in advance!

Regards,
Bert