"Before you hail him, you must be flagged both from killing Bertoxxulous and rescuing Mylik and Adler. You must also have an unmodified skill of 220 in Blacksmithing."
"Before you hail him, you must be flagged from killing Terris-Thule. You must also have an unmodified skill of 220 in Brewing."
"Before you hail him, you must be flagged from killing Saryrn. You must also have an unmodified skill >= 220 in jewelcraft."
"Before you hail him, you must have talked to Maelin to go after Rallos Zek. You also need an unmodified skill between 200 and 250 in pottery."
Actually you need quite alot more than valor flagged.