Preheat grill or broiler. In small bowl, thorughly combine cream cheese, sour cream horseradish, and mustard. Refrigerate until ready to serve.
In medium bowl, throughly combine contents or marinade package with vinegar, water, and Worchestershire sauce. Place beef cubes in marinade; pierce deeply with a fork.
Marinate 15 minutes, turning occasionallly. Thread small skewers with meat. Grill or broil beef 5 to 6 inches from heat, 8 minutes per side for medium. Baste with remaing marinade.
Serve beef with horseradish sauce.
Servings: 4