Train/Tube Oystering - E. Croydon to St Pancras/Kings Cross

I have an Oyster card that is auto-topped up if it falls below £20.
Currently I only use it on the buses, but I wonder if it's yet
possible to do the following with this card:-

1] Travel from East Croydon to St. Pancras by Thameslink train.

2] Travel from E. Croydon to Victoria by tain, then from Victoria tube
station to Kings Cross tube.

I did one of those trips (can't remember which) in Feb 2007, and my
Oyster card let me IN but wouldn't let me OUT - so I had to pay a
penalty. I'd innocently thought it would be possible, and wonder if it
is now?

Adam.

Thanks to everbody who answered. A one day travel card it is, then.
I'd ordered train tickets online for a return trip to Newcastle from
East Croydon and had wanted to travel via Kings Cross Thameslink, as I
did the previous year, but the web site wouldn't allow it, so I'm
having to buy separate tickets for the E Croydon-Kings X journeys

I've since learnt that Kings X Thameslink station has closed, but that
I can do E. Croydon - St. Pancras instead. Now, wouldn't you have
thought that Gordon Brown would have personally informed me of this
important closure? When will that man ever learn?

Adam.