As I mentioned before it is best to avoid modifying the files included with mojoPortal. If you are making a custom page in your own project you would set that from the code behind.
We do currently have a way to show the email address on the member list but not on the profile view. To show it on the member list you could add this to your user.config file
<add key="ShowEmailInMemberList" value="true" />
this setting is primarily for intranet/private network environments, it would not be a good idea to expose email addresses of users who register on a public web site.
Hope that helps,