Actually, I just want to know if there is a way, in OpenERP, to manage customers emails by support ticket?
project_issue could give you what you need.
You might also want to have a look at the community extensions for it, available in the "Project Service" project. I have some contributions there I built to support a service management workflow - you can see an explanation here.
There is a module crm_helpdesk. According to the description:
Like records and processing of claims, Helpdesk and Support are good tools to trace your interventions. This menu is more adapted to oral communication, which is not necessarily related to a claim. Select a customer, add notes and categorize your interventions with a channel and a priority level.
This is not exactly what you want. Another option might be project_isue:
This application allows you to manage the issues you might face in a project like bugs in a system, client complaints or material breakdowns. It allows the manager to quickly check the issues, assign them and decide on their status quickly as they evolve.
If both of these default modules do not do what you want, searching on the internet might give you a module better suited, or you can build your own module(s) to do what you want.