I created a war and deployed it to my $CATALINA_HOME/webapps folder just fine. Then I wanted to test configuring it to point to a war at an arbitrary location such as c:\\tmp\\
If you want to have a site available at http://myhost:8080/myTestContext, put the following in $Catalina_home$/conf/localhost/whateveryoulike.xml
http://myhost:8080/myTestContext
$Catalina_home$/conf/localhost/whateveryoulike.xml