To deal with it I found a way to accept EULA directly from the appliances shell console:

• Login to the vCenter server appliance shell console (default credentials:root/vmware)
• Navigate to the /etc/vmware-vpx folder: cd /etc/vmware-vpx
• Create empty file eula.accepted with: vi eula.accepted and save it: :wq

You can now start vCenter Service from the console with:

• service vmware-vpxd start
• service vmware-vpxd status