Hi again, Gary.
I'm sorry to hear your kitten is still experiencing the continued problem with constipation.
Light Karo syrup can be used very moderately (1 drop to 15cc of formula is fine), for constipation, and if you're able, try this 'kitty glop' formula in place of the Just Born you're using; it's been used with success in young kittens who are being hand-reared:
1 can evaporated milk (sweetened condensed)
2 tbsp. plain, unflavored yogurt (not low or non fat)
2 tbsp. mayonnaise ('real', not light or No-Fat)
1 tbs. Karo Syrup (light)
1 pkg. Knox gelatin
1 egg yolk (beaten)
1 cup unflavored children's Pedialyte
1 jar Beechnut Stage One Baby food chicken (if you use any other brand, make sure it contains NO onion, onion powder, garlic, garlic powder or any other seasonings/additives)
Mix milk, yogurt, mayonnaise, baby food, and syrup together well. Bring 1 cup pedialyte to boil and mix in Knox gelatin. Set aside. Mix egg yolk with small amount of milk mixture and beat well.
Add gelatin and pedialyte to milk mixture and beat well. Add in egg yolk mixture and beat well. Remember to not use egg substitute and keep egg white to a minimum.
Pour into bowl (with cover) and set in refrigerator. Glop will last for two weeks covered in refrigerator. Try freezing the mixture in ice cube trays and store the cubes in the freezer, thaw as many as needed.
Always warm glop to room temperature,(milk form), or a little warmer, before feeding.
You can continue to gently use the very well lubricated thermometer, but not every day and not more than once a day, if you are getting results with a b.m., with this.
The kitten should be evaluated by the vet if she is still having such a hard time with these infrequent, hard stools.
You can begin introducing 'solid' (quality kitten canned) food, in about 5-7 days, and make a very soupy 'gruel' she can lap, with the canned kitten food mixed with the formula, and continue to add the vegetable or mineral oil and karo syrup to the mixture, if she's still constipated.
Here are some sites with additional information re: raising orphaned kittens--
I hope things improve, soon.