Not able to get reports with API

Hello,

i am trying to retrieve Usage Meter reports with an API - Call, but all calls result in "HTTP/1.1 403 Forbidden" We are able to retrieve customers, to retrieve list op reports, we even get an error that the the License Set does not exist if we intentionally set the licenseSet - Parameter to a value that does not exist.

Our Query URL looks like this

https://xxx:8443/um/api/report/4?dateFrom=2013050100&dateTo=2013060112&licenseSet=vSphere%20VSPP

We are Using vCloud Usage Meter 3.0.2