There are a number of options for the RDS-TMC in Europe:
1/ Round plug receiver requires the accessory mount for the extra connectors, this mount is supplied as a windscreen sucker style or Brodit Pro-Clip style attachment.
2/ Mini USB style receiver which plugs in to the existing mini USB socket on the mount supplied with the device, the existing power addaptor is then plugged into a Mini USB socket on the side of the RDS receiver, this powers both the receiver and the device at the same time.
3/ Accessory mount with Built in RDS receiver, probably the neatest solution of the lot as it avoids all the "Spaghetti" aerial wires that you get with the previous two.
4/ A newer receiver combined in to the power lead, whilst this is listed on the TomTom web site I have not seen it available for sale as yet as a standalone accessory, again this receiver avoids a lot of the Spegheti mess in the cab of the car.
The above is fine for the x40 series, for the x50 only item 3 will work AFAIK - Mike