Can't rig an IK Spline to Weighted Bones?

[Shrooblord]

Hey forum,

I'm creating a character rig for a model I've created, but I'm running into a problem: my rig is that of a creature who has his head as his body, much like you'd imagine a life-sized emoticon to look like. So I need to have both facial rigging and 'spine handling'. I'm currently following these two tutorials:

https://www.youtube.com/watch?v=0_0quIDxlOw

https://www.youtube.com/watch?v=az9Iycp3fGE

I've already watched a great part of the Maya official tutorial series, up to the part where they rig the neck.

I can rig a new set of bones with an IK spline.

However - my bones that are already in my character and have skin weights associated to them cannot seem to be effected by the IK spline. When I create the spline, the control vertex is never created...? I can drag around the IK spline's CVs, but the bones never follow. I have tried creating clusters to control my IK spline with, but it won't make the bones budge.

Why do my bones not follow my IK spline curve?

Thank you for your help,

Shrooblord