After selecting Services, Adding a new service, selecting ERP5 and the latest release, you should reach the KVM configuration menu.
Note, that at the time of writing, the configuration for ERP5 has to be provided in the XML textarea on the form displayed. Enter the following:
Partition Amount: 15
Pre-selected Software Release: software/erp5
Automatically Deploy Software: true
Automatically Deploy Instances: true
Automatically Run Sofware/Instance: true
Custom Frontend Backend URL: <Leave empty, fill after instance creation, see below>
Custom Frontend Backend Type: zope
and then click Proceed to begin compilation.