I think some of the information given in the forum or in presentations should be added to the documentation that comes with the plugin.
For the mapping to work on the receiving server side, one of two conditions has to be met.
1) The WP install has to be using a dedicated IP address with one wildcard vhost.
2) Every single domain that is going to be mapped has to be added in a ServerAlias directive inside a vhost. This can be done by simply parking the domains locally.
Any other solutions?