How to disable http redirect to https on routers?

[#1]

I have only one 'secure' VirtualHost setup for an environment (let's say dev envronment). This VirtualHost has SSL enabled, on port 9006:

https://<mgmtserver>/v1/organizations/<org>/environments/dev/virtualhosts/secure

{
    "hostAliases": [
        "xxx-dev.<domain>:9006"
    ],
    "interfaces": [],
    "name": "secure",
    "port": "9004",
    "sSLInfo": {
        "ciphers": [],
        "clientAuthEnabled": false,
        "enabled": true,
        "ignoreValidationErrors": false,
        "keyAlias": "alias",
        "keyStore": "myKeystore",
        "protocols": [
            "TLSv1",
            "TLSv1.1",
            "SSLv2Hello",
            "SSLv3"
        ]
    }
}

There are no other VirtualHosts setup for same environment:

https://<mgmtserver>/v1/organizations/<org>/environments/dev/virtualhosts

[ "secure" ]

The API Proxy uses only "secure" virtualhost in the proxy endpoint configuration.

The http://xxx-dev.<domain>:9006 gets redirected to https://xxx-dev.<domain>:9006 (through 307 redirection status code). Where can I disable the HTTP to HTTPS redirect?