vApp Export OVF Template fails with VM's are in a Resource Pool

I'm wondering if what i'm doing is right/wrong ..

I have a resource pool  DEV  which i have 2 virtual sites Site1 and Site2

     In this resource pool DEV  i have 2 vApps Site 1 and Site2

          In the vApp Site1  i have another resource Pool Site1 and a number of  vm's are placed in this resource Pool

               This allows me to managed the resources of the vm's in this vApp (ie shutodown/update)separately to the root

                    Resource Pool and other vApp Site2

But when i shut down the vApp Site 1 and try to export OVF Template, i get an error

The operation is not supported on the Object

Call "OvfManager.CreateDescriptor" for object "OvfManager" on vCenter Server "vCenter Server namet" failed.

The only way i can export ovf template is by removing the Resource Pools ??

Am i mising somthing here , or am i going about managing the vApps/Resource Pools wrongly ??

regards

Paul