If you have a script (which doesn't immediately terminate) you can do

osso-xterm -e your-script.sh

An example (instead of your-script.sh I just use 'vi'):
#!/bin/sh
osso-xterm -e vi

You can test this interactively with
osso-xterm -e vi
in an xterm.
It'll launch another xterm which runs 'vi'. Try it, then drop back to multitask view - you'll see two xterms, the one you ran 'osso-xterm -e vi' in, and a new one with just 'vi'.