It looked straightforward but like all these things I haven't done, I er...can't do it. I only spent a couple of minutes looking at it, but roughly, I thought all I needed to do was lube the valve up with some tyre paste and push it through from the outer side of the wheel (i.e. from inside the tyre, if the tyre was on).
But it's being difficult! It wouldn't push through. Do I need to use some kind of press? (which I don't have

) Would one of these tools do anything:
http://automotospecializer.com/shop/...DAM-TT-0002%26 it only mentions valve removal but you never know...
Or do I just need to persevere and it will push through eventually? I could warm up the valve on a radiator first, might make it more supple.
Help!