And remember that the Hawk
was stuck in traffic for a while; I bet Vaklu and his cronies staged the blockade knowing that the Exile was headed for Onderon, tipped off either by his Sith allies or Atris.
As TKA-001 said, it wouldn't be difficult to pick out the Hawk
, considering that it's of a rare class of ship. And as Totenkopf said, the general probably had all his manpower searching for the other general.