Asterisk w/ Billing Module to be coded with Ruby on Rails

Looking for senior level Asterisk softswitch developer with Billing module development experience using Ruby on Rails. PHP experience is a plus. Speaking English fluently and MYSQL experience is a requirement to manage the projects. The project scope is to work on an already developed softswitch in order to fix existing issues as well as creating new features. Currently the existing softswitch has no billing module created for it therefore we require this module to also be developed for it. AGI scripting is a must as well