Connections and add pssnapins in functions, scope?

I thought I was being so smart, I decided to create a couple of functions and add them to my admin module so I could connect to my vCenter server so I could use my PowerCLI and to my Domain Controller so I can us my Quest snapins.  But, when I run the command, I get connected but it doesn't stay connected at the prompt and the snapins don't stay loaded.  I know I an get this done using my $profile, but I would rather have it only connect when I run a command. How do I make this work and stay working?  I am pretty sure this is a scope issue

function Connect-ADVsi{

    Param(

        [string]$User = 'dom\dadmin',

        [System.Security.SecureString]$PWord = (ConvertTo-SecureString –String "!password@" –AsPlainText -Force)

    )

            Add-PSSnapin Quest.ActiveRoles.ADManagement

            $Credential = New-Object –TypeName System.Management.Automation.PSCredential –ArgumentList $User,$PWord

            Connect-QADService -Service 'dc.dom.com' -Credential $Credential

}

I can kind of get it to work if I run it like this:

$test = Connect-ADVsi

Get-QADUser dadmin -connection $test

But if I just run Get-QADUser dadmin, 

I get this:

Get-QADUser : The specified domain either does not exist or could not be contacted.

At line:1 char:1

+ Get-QADUser diverso

+ ~~~~~~~~~~~~~~~~~~~

    + CategoryInfo          : NotSpecified: (:) [Get-QADUser], COMException

    + FullyQualifiedErrorId : System.Runtime.InteropServices.COMException,Quest.ActiveRoles.ArsPowerShellSnapIn.Powershell.Cmdlets.GetUserCmdlet

And this how I would like it to work, Get-QADUser dadmin, after I make a connection.