As described in Defining targets and Creating gateways, you can upload an XML file that describes a user-defined transport. You use Manage Transport Types to upload the file. After you upload the XML file, the transport becomes available for use when defining a target or gateway.
The XML file that describes the user-defined transport includes the attributes for the transport. These attributes are displayed (in the section Custom Transport Attributes) on the target or gateway page when you specify a user-defined transport. For example, a user-defined transport for a gateway might include the attribute GatewayRetryCount.
The person who wrote the XML file describing the transport can update the attributes (by adding, deleting, or modifying the attributes).If the XML file is modified, you again use Manage Transport Types to upload the file. Any changes to the attributes are reflected in the gateway or target page.