You certainly appear to be in a dilemma, one of the few people who can't find a toad in their backyard? And I wanted to express my gratitude for not automatically trying to feed the salamander to the hognose, but instead using it only for scenting!
I don't recall offhand the percentage of salamanders found in western hognoses stomachs, but I do believe it to be extremely low. Although it is easy to assume that a hognose will recognize any amphibian as a food item, it may not necessarily be true for caudates. Nonetheless, I have had experience with scenting a mouse with a captive gray treefrog, and the wide variety of scenting sources are demonstrated in the link below.
If it has only been a few weeks, my standard/cookie-cutter advice for people on this forum is to give it more time. If you scroll through the forum over the last few months you will certainly find some people who have had hognoses go mysteriously off feed for several months. It appears that the most problematic period for hognoses is when it first gets purchased!
My bottom-line advice is to not worry about the salamanders or buying a toad, instead focus on giving it more time, reduce the amount of disturbance to the snake, and since scenting with tuna fish seems to be the most successful method, try that next!
http://forum.kingsnake.com/hognose/messages/5710.html
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"I know the human being and fish can coexist peacefully."
Governor George W. Bush, Jr.
"Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us."
Calvin and Hobbes (Scientific Progress Goes 'Boink', 1991)
