Guys I did it! Yesterday I sat down to get my Poker II fixed. I've never soldered or desoldered anything before, so I went to check out some YouTube videos and GH threads first. Besides I received a lot of help and support (and the stem that I changed) from a german mechanical keyboard community on computerbase, which is a general computer/tech community (on which some keyboard enthusiasts have gathered).
As I have already posted my keyboard came with 2 broken caps and one broken stem. The seller has agreed to ship me those but I figured that I wanted to go straight for repairing the switch at least as it looked terrible and made my heart bleed. The only thing I really had to do was to desolder the LED and switch (although I guess I could have opened it without desoldering it?) and change the broken stem.
It's a black stem, but I don't mind
Anyway, here are some pictures: