Powershell explicit remoting for Exchange does not work from module

I am trying to add Remote Implicit functionality to  existing Exchange module to allow users to run Exchange cmdlets from their workstations.

Remoting works fine when I use script below:

------------------------------------------

function Enable-ExchangeExplicitRemoting {cmdletbinding()]
param(
[Parameter(ValueFromPipeline=$true)]
[string]$exchServer
)   
Write-Verbose "Creating PSSession.."
$global:s = New-PSSession -ConfigurationName Microsoft.Exchange -ConnectionUri http://$exchServer/PowerShell/ -Authentication Kerberos

Write-Verbose -verbose "Importing PSSession"
Import-PSSession $s -Verbose -AllowClobber |out-null
}

Enable-ExchangeExplicitRemoting -exchServer "servername"

VERBOSE: Importing function 'Add-ADPermission'.
VERBOSE: Importing function 'Add-AvailabilityAddressSpace'.
VERBOSE: Importing function 'Add-ContentFilterPhrase'.

.........

get-mailbox

.. mailbox info returned....

---------------------------------------

As a result. I am able to run Exchange cmdlets on remote server and get the data back.

However if I add this function to an existing module , and then load this module , the commandlets are not available:

------------------------

Import-Module Exchange

get-command Enable-ExchangeImplicitRemoting
CommandType     Name
-----------     ----
Function        Enable-ExchangeImplicitRemoting

Enable-VTBExchangeImplicitRemoting -exchServer "servername"

VERBOSE: Importing function 'Add-ADPermission'.
VERBOSE: Importing function 'Add-AvailabilityAddressSpace'.
VERBOSE: Importing function 'Add-ContentFilterPhrase'.
.......   
get-mailbox
The term 'get-mailbox' is not recognized as the name of a cmdlet, function, scrip