During the initial configuration of each cloud cell, you specified an HTTP service IP address. By default, vCloud Director uses that address in the XML responses from the REST API and as the upload target for the transfer service (for uploading vApp templates and media). To use a different address, specify a public REST API base URL.
This is untrue.
By default (public addresses not configured) vCloud Director uses the "host" HTTP header in all XML responses except for the upload target for the transfer service. It uses the HTTP service IP of the cell.