Wash the beans well under cool tap water; drain and cut into lengths to fill pint jars. Pack the beans into sterilized, hot jars; add the pepper, mustard seeds, dill seeds and garlic. Combine the vinegar, water and salt and bring to a boil in a non-reactive saucepan. Pour the boiling liquid over beans, filling to one-half-inch of the top of jar. Cover with the jar lids. Process the jars in boiling water for 10 minutes (start the count processing time as soon as the water in canner returns to boiling). Remove the jars and complete seals (tighten the lids) if necessary. Set the jars upright, several inches apart, on a wire rack to cool. Chill at least 1 week in refrigerator before serving.
If you are uncertain about any steps in canning, feel free to check out several canning websites or call your local Cooperative Extension Service, if you'd rather personal advice. Also, you can read the directions in the box in which the canning jars are packed.