I've finally got the card. It is indeed only the Platinum MasterCard. Form the time Barclays sent the card by the time it got here the credit line had been slashed from 20K to $500 (serves me right to apply to 4 credit cards at one time).

But, the specific terms and condition for the Miles and More Platinum MasterCard states:
"No mileage expiration: all unused miles, which have been awarded to your Miles&More account and those you will earn in the future remain valid for an unlimited period of time and will no longer expire provided that you make a purchase for which miles are awarded at least once a month and have held a Miles&More MasterCard for at least three months."

This was confirmed by Barclays card services department. Of course they had to state it in the negative, miles will be lost after 36 miles unless you will use the card every month.

So it seems to be a very good deal to keep the miles open. Hopefully come March 2009 I will not discover all my miles are gone.