Similar to above I have this in my Powershell profile, I do not ever do anything with -Prefix though
function Connect-ExchangeOnline
{
Set-ExecutionPolicy RemoteSigned
$usercredential = Get-Credential
$Session = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri https://outlook.office365.com/powershell-liveid/?proxymethod=rps -Credential $UserCredential -Authentication Basic -AllowRedirection
Import-PSSession $Session -AllowClobber
Connect-MsolService -Credential $usercredential
}