If you are talking about skewing the text so that the verticals of the characters remain vertical, that is Type>TypeOnAPath>Skew. (Was only added, as I recall, around AI10--many years behind other apps.)
Shear might work, but I've never done that with text on more than one line or on a path.
With shear, though, you're not really italicizing the text; you're really just slanting the text object itself.
Other options may include outlining the text once you have it in place, making it a compound path/object and shearing or using the free transform tool. Even if that does work (and I'm not placing any money that it does), it's a LOT of work to get it right.
Default back to Harron: if you absolutely need this font to be italicized, pray to everything sacred there's an italicized version and buy it.