[TYPO3-english] Insert URL parameter into Powermail hidden field

[Tony Lush]

I am trying to insert a URL parameter into a hidden Powermail field.

The URL might be mysite.com/quote.html?product=tshirts

In the Powermail template's Setup I have:

plugin.tx_powermail_pi1.prefill.uid24 = TEXT
plugin.tx_powermail_pi1.prefill.uid24.data = GP:product

Where uid24 = the hidden Powermail field

The product parameter does not appear in the data stored.

Can someone suggest a solution?

Best regards -- Tony