MONSTER and PROJECTILE flags together?

[Fractavius]

I have been playing some Teleglitch, and one thing that really interested me about the game is the way melee monsters come at you. They're basically homing missiles with fairly crappy turning, charging straight at you and making wide turns when they miss, bouncing off walls if you're too close to one as they try to reorient themselves. Its quite fun because even though their movement is predictable, they are faster than you and the turning renders backpedalling alone an ineffective strategy at avoiding them. I thought it would be cool if I could copy that behaviour in ZDoom using seeker missiles, but its not working too well. Is it actually possible to get these two flags to work together?

I tried adding +SEEKERMISSILE, -NOGRAVITY, -NOBLOCKMAP, +SHOOTABLE to the Demon's flags and changing it's Spawn state to A_Seekermissile(0,8) and ignoring the See state. Then I got a modified monster to shoot them at me. The problem is if I also have MONSTER or +ISMONSTER set, the demon doesn't do any damage, as well as just clips through me before trying to come round back at me again. Despite having Bouncetype Hexen they also don't really bounce off walls, they crash into and hug it until I come round and lure them away from it.

If I don't put the +SEEKERMISSILE flag in, the demon instantly dies when it is shot out, and the spawner monster is basically just littering the map with corpses.