Trim and discard all visible fat from the roast. Place trimmed roast in a slow cooker. If desired, the roast can be browned prior to placing it in the slow cooker.
In a medium bowl, combine soy sauce, bay leaves, peppercorns, rosemary, thyme and garlic powder. Pour over roast.
Add the beef stock and enough water to almost cover the roast, leaving about 1/4-inch of the roast above the level of the liquid. Cover and cook on low heat for 8 to 10 hours, or until meat is very tender.
Remove meat from broth and set aside on a cutting board. Reserve broth. Slice roast thinly or shred with a fork. Cover to keep warm while preparing rolls.
Set oven to broil. If rolls are not already sliced, slice them in half lengthwise down the side of the roll. Lightly butter the cut side of each half. Place buttered side up on two large, shallow baking sheets. Broil until golden brown.
To serve: place meat on prepared rolls. Pour broth into 8 individual ramekins for dipping sandwiches.