WebDirect Homeurl and SSO

This may be a really stupid question, but I’m trying to add the homeurl for links to an app accessed via WebDirect. However, we employ OttoFMS SSO and it appears to remove the homeurl information when users are prompted to login. Is having the homeurl retained simply not possible when using SSO? While it isn’t crucial that it works because I hide files on the WebDirect launch screen, I do have external users that I’d rather land on a friendlier page.