vRO 6.0.1 compatible with vCenter 5.5 Update 1a

from the VMware Product Interoperability Matrixes, it states that that

vCenter 5.5 Update 1a is compatible with vRO 6.0.1!

but if you then check the

VMware vSphere Web Client , it states that only VMware vSphere Web Client 6.0 is compatible with vRO 6.0.1 ?

So my question, I'm currently missing the vRO 6.0.1 from Web Client, could this be the issue ?

and do I have to deploy the 5.5 appliance for vSphere 5.5 ?

I was just hoping, to deploy the latest, or is this simply down to deploy 5.5 with 5.5, and 6.0 with 6.0, and 6.0 is not backwards compatible ?

Does anyone have any expereicne of vRO 6.0.1 with vCenter vCenter 5.5 Update 1 ?