Sorry another daft remote keys question

[j0hn]

So following on from my previous thread, I split my knackered key apart (the one that was held together with insulating tape - the bloke I bought the car from said he never used it and assumed the yellow tape designated it as a spare :no: ), took the badge off, removed the transponder and flick blade (as a unit, rather than splitting the blade from the holder) and put it into the shell of a new key*. I have a couple of questions at the bottom and the bit in the middle may not be relevant to those, but read on if you don't mind!

This is the good bit, I took the key out to the car (I knew at this point the remote wouldn't work) to make sure I had not knackered the transponder, put it in the ignition and it started - which is nice. I then attempted to code the remote using the working key in the ignition (with the ignition on), locking the door and pressing the button (I assume twice as I am trying to code a second remote). Nothing happened.

This is not such an issue as I've just pulled the rest of the crap key apart and put the PCB and transmitter into the new key's case and Bob is indeed my uncle.

Currently I have two fully functioning keys (1 as new and 1 scabby one), one new one that doesn't work for my car and enough bits to make up a 4th.

One is marked 1K0 959 753 G, which I understand is the latest revision of the standard 3 button flip key and one that took all the parts out of the worst scabby key. The other is marked 3T0 959 753 and looks like this:

DSC_5690 by jonnyguitar, on Flickr

Rather than splitting into two, you only seem to be able to remove the battery cover of the 3T0 key, so whilst I assume I can remove the badge and take out the screw to get to the blade and transponder, I can't get to the circuit board. The LED is also up near the top of the key.

*Now - I came across these two new keys by way of ebay - both used as spares from the same car but never used - the blades have never been in a lock or ignition and they have never rattled around with the loose change in someone's pocket. I naïvely assumed at the time that I could recode the remotes and transponders using the key in the lock method but I now know I can't do the transponder with the neccessary code. However, for £12 each I have a couple of new complete keys rather than the pattern cases for £7 or £8 or whatever. I knew the blades would be useless but had decided that either way it would cost me to either get a blank cut (probably a Chinese version of the HAA) or get a proper HAA and have it cut anyway - there was some logic to my purchasing. Plus I had money in Paypal.

Questions:

1) As the keys I've bought are effectively used, can I reprogram a remote that was already attached to another car to my own car? If I leave the battery out for long enough, will it lose its memory?

2) My original keys are 1J0 959 753 AH - apparently superseded by *DA code keys. Both of the new keys are marked 434 MHz - as they have different codes, are they not compatible?

3) Is anybody familiar with the type of key I've posted the picture of up there? Can it be taken apart?

I think that's all I wanted to know for know, but if anybody can shed any more light on what the hell I've done, I'd be grateful!

Ta