I'd suggest asking for support on the application support channel. Perhaps they have a dependency on some new shiny version of Curl that no-one ships yet? [by TrevorH]
I've been stuck for days on how to enable curl Request engine support for Oauth. Some have suggested having the curl-devel package installed but I noticed this is not installed on a different server - and phpinfo actually shows the info below, which is what we want for our application to work 100%.