The only Star Alliance route out of LBA that could easily get you to/from the USA is to BRU, so if you wanted to go from LBA that's your only option. The connecting flights from there to IAD do indeed only have Y available around your travel dates so if you want Business, then there's 3 options :

1 Wait and hope a business seat opens up.
2 Have a look at the Star Alliance timetable, at the 2-stop options that are available LBA-BRU-XXX-IAD, where XXX could be VIE or CDG or FRA etc, though this will be a tortuous trip.
3 Forget LBA and go from somewhere (MAN springs to mind) which is more richly endowed with Star Alliance flights.

Strongly recommend, if you haven't already done so, to sign up to ANA as detailed in the Sticky, so you can do your own research for available routes and award seats.