Very close to the bus terminal there's an on-ramp to the N4. In August 2010 there were was some work on the road and guaka was told not to hitch on the N4 itself. The on-ramp looks like a good hitching spot but people are not very eager to pick up hitchhikers there.
East towards Luxembourg, Germany, anywhere?
There's a local bus into Luxembourg (the country), 1,50 EUR for a ticket valid for 2 hours, including changing bus or train in Luxembourg. You might be able to reach one of the excellent gas stations on the Luxembourgian highways with such a ticket.