Profile create fails for non-standard ssh key paths

When I triton profile create I get a list of keys like this:

The fingerprint of the SSH key you want to use to authenticate with CloudAPI.
Specify the fingerprint or the index of one of the found keys in the list
below. If the key you want to use is not listed, make sure it is either saved
in your SSH keys directory (~/.ssh) or loaded into your SSH agent.

1. Fingerprint "e:f:g..." (4096-bit RSA)
   - in agent: /path/to/some/id_rsa

2. Fingerprint "a:b:c..." (2048-bit RSA)
   - in agent: /path/to/joyent/id_rsa

These keys are not in the standard location inside ~/.ssh in this case. When I pick one of them it then fails:

triton profile create: error (Setup): could not obtain SSH private key for keyId "a:b:c..." to create Docker certificate

Reproduce the failure with triton profile create while selecting an SSH key loaded from a non-standard path. Start at the profile-creation flow and trace how the selected key is used to create the Docker certificate; done means profile creation succeeds for that key.