How can an explorator acquire servitors/servo-skulls/etc? What requirements should he meet to turn an enemy into a servitor? (that is to capture the enemy alive, and make all the procedures required by himself).
I would suggest a reasonable amount of Medicae/Tech-Use to convert someone into a servitor. A servitor reclamation facility would also be useful.
The process is along the lines of performing a lobotomy (Medicae), installing new bionic hardware (Medicae/Tech Use), and programming (Tech Use). Servitor reclamation facilities will have equipment designed to help automate the process somewhat. It's something of a hand-waving in the game mechanics, as I recall - they don't really detail what you need to do.
An Explorator could also requisition new servitors/servo-skulls from a Mechanicus facility.
As an added bonus, I recommend the Minion rules from Black Crusade for designing your servitors/servo-skulls.