In large bowl, blend soup mix, oil, vinegar and garlic; stri in potatoes.
Grease 30x18-inch heavy duty foil; top with potato mixture. Wrap foil loosely around mixture, sealing edges airtight with double fold. PLace on another sheet of foil; seal edges airtight with double fold in opposite direction.
Grill, shaking package occasionally and turning package once, 40 minutes or until potatoes are tender.
Spoon into serving bowl and toss with basil and pepper. Serve warm.
OVEN METHOD** Preheat oven to 450*. Prepare foil packet as above. Place in large baking pan on bottom rack and bake, turning packet once, 40 minutes or until tender. Toss and serve as above.