All the parts to replace the indicator lamps should be available from a dealer if you let me know which parts are being difficult ill try and find a part number for you but as your model of sportster first appeared in 94 i have a parts list for the 94 sportster and from on line i have found that most parts were still the same in 99 so they had a long life
otherwise you may need to start looking through the zodiac or custom chrome catalogues for alternatives which are often more expensive and of lower quality
Brian