Connect-CIServer to VCD as sysadmin ?

Hello,

I do have issues when connecting to VCD using a user as sysadmin role.

It works when I log to an org with using user with Org_admin

Connect-CIServer -Server 'xxx' -User 'user_org_Admin' -Password 'zzz' -Org 'wwwww'

OK

But when I try to log with a different user having a sysadmin role without giving any Org name,

Connect-CIServer -Server 'xxx' -User 'user_sysadmin' -Password 'zzz'

I obtain a 401 error

According various articles, it seems possible to log as sysadmin to VCD to automate ORG and VDC creation...

Any clue someone ?

Environment: server: VSphere 5.5 / Vcloud director ; client : Powercli 5.5 running on Win SRV 2008 R2