Property Keys In Maya : InheritType?

Hi,

I am currently writing an FBX exporter for one of our internal packages which
exports an animated skeleton.

The actual skeleton is exporting fine and imports into maya perfectly.  However
we also want to add extra animated properties to some of the joints.  These seem
to appear OK in the ascii version of the fbx file we generate but they do not
appear as animated attributes in the scene in maya.

It is probably something small but I was wondering what we might be missing, our
code (rougly) does this (I am retyping as I don't seem to be able to copy and
paste into this window - so apolgies for typos)

prop = KFbx::Create(pNode, name, type)
prop.ModifyFlag(KFbxUserProperty::eUSER, true)
prop.ModifyFlaf(KFbxUserProperty::eANIMATEABLE, trye)
curve = prop.CreateFKCurveNode(takeName)
curve.FCurveGet->KeyModifyBegin()
....Write SOme Keys
curve.FCurveGet->KeyModifyEnd()

As a hint when I am look at the ascii version of the file we create compared to
the one which maya creates when we saved a working version I noticed that the
maya generated one has this in it...

Property: "InheritType", "enum", "", 2
where as the one we generate has this
Property: "InheritType", "enum", "", 0

When 'hack' our file and set this value to 2.  Our file loads correctly into
maya with the extra keyed attributes.  

So is there just a flag I need to use?

Many Thanks