(Hillsboro, OR)  --  Two teenage boys are in custody, following a robbery at a Hillsboro Plaid Pantry store.  Washington County sheriff's deputies say the teens used fake guns in the holdup, which happened shortly after midnight.  Police say they found the boys, ages 14 and 15, hiding in a used car parking lot not far from the Plaid Pantry on Southwest Baseline.  Investigators tell KATU-TV they're trying to determine whether there's a connection between the Plaid Pantry robbery and an earlier holdup at a Carl's Jr. restaurant.