I called TG in Norway and they confirmed that TG only accepts Visa and Mastercard, at least from Scandinavia. They told me to just finish the booking and without paying, and then call the TG ticket office in the country I was traveling from to finalize the booking.

Since my booking was Ex CDG I ended up calling TG in France and then 25 minutes later and some French/English later, my Am Ex was in the system. 30 minutes later I received a confirmation mail in my mail box.

I find this to be a very complicated and backwards way to make a booking, but except from the language problems and spending 20 minutes listening to TG Frances waiting music, I am pleased with the service TG ticket offices in Oslo and Paris gave me ^

But come on TG; in 2011 you really need to offer more than just Visa and Mastercard to all your customers!!