Service blueprint, conditional items on forms

Hi,

I have a service blueprint that fires off a vco provisioning workflow. On the request form I have a drop down box with a couple of options for clusters, I want to only show some other fields on form if certain clusters are selected.

I have tried using constraints-visible-conditional for this, all the settings look ok but it never draws the field if the conditions are met.

So the question is, does anyone know if this form is dynamic or static, must the (in this case) cluster field be set in advance of this form being drawn ?

Cheers

Thomas