[TYPO3] typoscript: insert values

[Markus Friedrich]

Hi,

I'm trying to evaluate a value with typoscript and to reuse it. Normally 
I have a variable like this:

getdate = 20080207

What I now want to do is something like this:

getdate = TEXT
getdate.data = date : Ymd

The value of getdate must be something like '20080207', the construct 
must be evaluated before it's passed to the extension that uses this 
variable.

Is there a possibility to do this?

Thanks in advance!
Markus Friedrich