Achievement - The Hatchery's Secret (BUG or not?)

I need help. I want to do anything in Killer Intinct, and this achievement makes me bad.

I follow this tutorial: http://www.trueachievements.com/a219134/the-hatcherys-secret-achievement.htm

But because the achievemente “Hoarder”, you need to collect 50 different items in your Shadow Lords Storage. I collect WYVERN-X, Security codes and a transceiver form hatchery quest at the same time. But now, the mission “Village under attack” i choose “Command the stalkers” and after the battle o choose “Agree to help” and now the game dont initiate a new quest entitled “Search for stalkers” for me, and i cant collect 5 tranceivers now, to enter again in the hatchery and complete this achievement.

I really need help. This achievement is missable now? Any chance for me to initiate “Search for stalkers” and continue this achievment? thanks to all ;(