I've had this same problem too, first tries to get the propper amber bulb with offset pins but no good. So I bought some amber glass paint of ebay for a few quid gave the whole glass part of the bulb 1 coat and a year later still flashing amber. Job done.
http://cgi.ebay.co.uk/ORANGE-MARABU-15ML-JAR-TRANSPARENT-GLASS-PAINT-GLASART-/310227168629?pt=UK_Crafts_Glass_Art_Supplies_CV&hash=item483afaed75" onclick="window.open(this.href);return false;