Vietnamese preferred: Looking for senior developer to manage and extend our website CMS system - long term employment -- 2

We have a vietnamese developer team who write structured code. They should now move on to other projects and I want to outsource our website management software project to a senior developer. We have created our custom-designed CMS system and this allows us to manage multiple websites. The system is up and running but there are always new improvements we need to add. As such, I need a developer at senior level who can read the code and understand the system by himself and then add to the code in a structured way. This will likely be a long term, possibly full time employment, but the performance and speed must be good. Due to time zones and language barriers, Vietnamese are preferred. The requirements are: 1) Skype availability 2) No free time worker with another full time job, I need a self employed individual who is available during office hours. 3) NO DEVELOPMENT TEAMS!!!!! Only individuals. 4) No self tought developers. University level education in software engineering is MANDATORY Technologies requirement: - Web technologies (HTML / CSS / Javascript) - PHP - A custom-framework built on top of Symfony 2 - MySQL - Linux - Apache / nginx - AngularJS - Docker - Git - SEO