The full schema for configuring the undertow subsystem can be found in the wildfly-8.2.0.Final\docs\schema\wildfly-undertow_1_*.xsd files. I didn't see anything about redirecting URLs, other than automatic redirects to the https port, but I may have missed it.
Thank you very much, Greg, for this information. In the xsd file wildfly-undertow_1_2.xsd there are the entries file and reverse-proxy, but no rewrite.
Thus I conclude, that the URL rewrite cannot be done with undertow.