Hidden XForm controls

Hi,

Just a quick introduction - I have been involved in working
with the OOo project since its inception in testing, trying
out new features etc. I am also responsible for the knowledgebase
that is being used to offer another level of support. I am
interested in the XML side of OOo mainly for the XForms and
hopefully soon will see SVG in there somewhere as well :)

My first question to start things off for me is whether it is
possible to create a hidden XForm control? I can create a
hidden control - which is basically a hidden field of unspecified
type, but I can't see any obvious way of binding it. I can also
create XForms controls that are bound, but can't seem to make
them invisible. I saw the Enabled option, but this just grays
them out. I want a solution that enables me to include proper
XForm controls with the option of making them invisible to the
user. Is this possible, if so how can I do it?

TIA.

Regards
Jonathon