You cannot upgrade directly from v8.x to v11, but you can go to v10, and then v11
You DO NOT need to uninstall v8.6
The v10d install is here
http://support.veritas.com/docs/279330
Install it in Demo mode (no serials) on top of v8.6, then install v11d on top of that and your local info (schedules, job defs, selection lists etc) should all be migrated forward
Be aware that there have been multiple reports of the v10 -> v11 upgrade trashing selection lists, so have your current install well documented before starting, unless you can recreate things fairly easily.