Damn, there is nothing written about Graftgold keys in Uridium 2
manual. On the other hand, it was not written even in Paradroid 90
manual. Nice find, but I am way far from ability to progress more than to some 4rd fleet of Uridium...
There is nice P-90 fanpage on Nemmelheim, but I haven't found any about Uridium
I would like to contact Andrew Braybrook or Steve Turner for this.