I have a few friends who are in a similar situation as you. And believe me each one I know is contemplating about quitting. Of course, they don't want to simply quit because after all they are being paid and no one wants to quit a paying job before having something concrete elsewhere.
I think being able to do what you want is more important in a job than anything else. IMHO,
you should start looking for a "developer" job elsewhere. You can quit your current company after you receive an offer letter from elsewhere. And about the pay, I am sure you will get an equivalent pay, if not the same.
But as far as how the new company will treat you, i.e. as a developer or a developer in a support engineer role, I can't say. So research the company that you apply to. Ask around. People who work or have worked for that company might be able to better tell you about the goings on of the company. That could give you an idea about what you could expect if and when you are hired by the new company.
Good Luck !!!