SCP/SSH deployment tasks do not support bamboo variables

When trying to use bamboo variables in an SCP/SSH task the deployment fails. It does work without variables.

See below:

• Finished task 'Download release contents'
• Starting task 'Create deployment folder' of type 'com.atlassian.bamboo.plugins.bamboo-scp-plugin:sshtask'
• Executing [mkdir -p /var/www/deployments/ota-install/${bamboo.buildKey}/${bamboo.repository.revision.number}/]
• stdout = []
  -5 stderr = [bash: /var/www/deployments/ota-install/${bamboo.buildKey}/${bamboo.repository.revision.number}/: bad substitution]
• [mkdir -p /var/www/deployments/ota-install/${bamboo.buildKey}/${bamboo.repository.revision.number}/] has finished. Result: exit code = 1