Then, Is there any way to send HTTP parameters through POST instead of GET ?
What do I have to modify in Url field (Inside device type)?

I'm using SNMP, but I want to send this parameters through POST to auto login into the device (With my default web browser). Since the username and password can be stored on the dude database, If can do that I won't have to remember the username and password for each device (something like opening winbox just clicking on "Tools -> winbox" on the contextual menu of one RouterOS device).Not possible. Also why not simply use SNMP monitoring for you UBNT devices?