If you need to customize your maven options, you can edit the ~/.m2/settings.xml on the endpoint, just like if you are editing it for a regular maven user. It is important to make the changes on the endpoint, not the FlexDeploy server, and make sure to perform the configuration changes using the same user that FlexDeploy will login as on the endpoint. You can copy the .m2 folder from another machine if that is easier, or install Maven on the endpoint so that it is created for you and then edit it. This is the easiest way to configure Maven to have settings that apply to all future workflows. The same configuration options can likely be added into the Arguments plugin input, but would need to be entered each time that a new workflow with Maven in it is created.
The following macros are not currently supported in the footer: