Setting the XSI_UNSUPPORTED_METASL environment variable should enable the MSL parser, so MetaSL shaders will show up in the Preset Manager. I believe you have to re-register mentalray.dll too.

So, in a Softimage command prompt:

set XSI_UNSUPPORTED_METASL=1
cmdreg mentalray.dll
xsi

I haven’t tested this myself, so no promises 😉

via www.si-community.com • MetaSL.