The BIND entry you have created is for the localhost loopback address. Has your hosting provided given you a public or private IP address for your server ? I guess they will provide the DNS so they just need to setup a MX record for enterprise.com that points to enterprise.dedi.hosting.net.
Really need a little bit more information to help so could you post the following please
dig enterprise.com mx
host `hostname` <- note backticks and not double quotes