If you mean the configuration definition which is specified via the resource-configuration tag in the plugin descriptor, then the answer is no. The definition must be statically defined in the plugin descriptor. The only exception is "open map" properties. These are map properties that can contain arbitrary simple properties of type STRING. To define an "open map" property in your resource config, just add a map-property tag that does not have any simple-property child tags, i.e.:
<resource-configuration> ... <c:map-property name="myOpenMap"/> ... </resource-configuration>
An example of an open map is the JDBC connection properties in a Datasource Resource's config.