K, then you have to do it on your own by parsing the Output and ask the user if a password is necessary.
SSH.Net can't help you here, since it is not part of SSH protocol.
Sounds like you can't use expect() since those password-prompts appear unexpected.
So you have to do it async and parse the shell output if it contains a password request.
But it isn't that hard.
The tests are a great source for examples, e.g:
https://sshnet.codeplex.com/SourceControl/latest#Renci.SshClient/Renci.SshNet.Tests/Classes/SshCommandTest.cs
Test_Execute_Command_Asynchronously() and further.
SSH.Net can't help you here, since it is not part of SSH protocol.
Sounds like you can't use expect() since those password-prompts appear unexpected.
So you have to do it async and parse the shell output if it contains a password request.
But it isn't that hard.
The tests are a great source for examples, e.g:
https://sshnet.codeplex.com/SourceControl/latest#Renci.SshClient/Renci.SshNet.Tests/Classes/SshCommandTest.cs
Test_Execute_Command_Asynchronously() and further.