I maybe able to lend some info regarding sorcery to anyone interested in it's effects. With some in agreement that Sorcery is different in regards to Psionics, how it is handled in Dark Heresy can be found in Disciples of the Dark Gods. One of the true books lending to the evil machinations before Black Crusades is even out. Simply put, Sorcery has a self titled talent called the Sorcery Talent. Equipping a non player character with one give you the right to be a Sorcerer and use the raw powers of the warp as a Wytch might do.
Basically summoning a daemon is one of the key principles of sorcery. It means that your Forbidden Lore Daemonology Skill comes in real handy when making a ritual or curse somewhere found in the Black Crusade Core Rulebook and also a small blurb of it found in the Tome of Excess. Daemon Hunter in Dark Heresy talks about daemons more in detail and some of the ways one can include them in game.
Basically, the ritual of summoning can take time. There are usually instruments involved in a summoning for a sorcerer. Wards, Hexagrams, candles, sacrifices, candles lit, incense etc... When a sorcerer wants to use his powers to summon, roll a modified FL Daemonology test affected by knowing true names or little info of the daemon. There is a chart with penalties and bonuses affecting the TN.
Applying psychic powers or psy rating are totally up to you and can give the effect of a empyrean sorcerer that is more than just a crazed adept. Anything outside a typical Khorne cultists usually fits a Sorcerer of any Dark god quite well and I am know using one of Khorne in my game. Little does the players know or even the npc is that he will meet his fate for using the powers of the warp against the acolytes. The Blood letter will eventually turn on him in the end.