You can add I-X support for OWL-S using files available in an add-on distribution. This contains the files needed to use I-X with the OWL-S API - http://www.mindswap.org/2004/owl-s/api/.
Unzip the OWL-s add-on file, which will be called something like "ix-version-owl-s.zip", in the directory in which you installed I-X.
Before going further, you may wish to save your existing ix.jar and imports/all-imports.jar because they are replaced to allow the use of OWL-S.
Then use etc/ix-with-owl-s.jar to replace ix.jar (move or rename) and etc/all-imports-for-owl-s.jar to replace imports/all-imports.jar.
Check that imports/owl-s exists and contains a fair number of jar files.
Note that we are not distributing the file upnp100.jar that is part of the OWL-S 1.0.0 API, because of licencing issues. It is not needed for any existing I-X applications.