Help with Google Checkout API

[ChurchMedia]

I'm working on a Google Checkout API. Right now I'm stuck with the settings field in the paymentapi table. All I need are two fields -- one for the Vendor ID and one for the Merchant Key. I don't know how to use datastore (would love to learn).

What does this code need to look like? It doesn't work as-is:

a:3:{s:17:"google_vendorid";a:3:{s:4:"type";s:4:"t ext";s:5:"value";s:12:"";s:8:"validate";s:6:"strin g";}s:6:"google_merchantkey";a:3:{s:4:"type";s:4:" text";s:5:"value";s:16:"";s:8:"validate";s:6:"stri ng";}}

Thanks!