Lync Custom Presence status

You can set several statuses such as a custom presence as appear offline, this is a well-known status in the Public IM world such as MSN Messenger.

Note: I have tried using custom presense as stated by others by using the local computer for the presence xml, this poses an issue with some company's that want full control over the presence.xml file. which localizing it to a webserver makes it very easy for changes to the document.

 
Appear Offline
Appear Offline is well known in some Public IM networks, in OCS 2007 and OCS 2007 R2 you can set the Appear Offline by a group policy for all users or by user through the registry.
With Lync this setting cannot be activated through a group policy or a registry setting, but this is set within the Clientpolicy. To enable this feature you can issue the following command from the Lync management shell:
Get-CsClientPolicy | Set-CsClientPolicy –EnableAppearOffline:$true

This command will modify the default client policy, if a user signs off and on the status can be set.

Custom Precense
It is also possible to create up to four custom presences. This can be done through a custom xml file.
What we need to have is a custom xml file.

<?xml version="1.0" encoding="utf-8"?>
<customStates>
  <customState ID="1" availability="Online">
    <activity LCID="1033">Working From Home</activity>
  </customState>
  <customState
    ID="2" availability="busy">
    <activity LCID="1033">Server Install/Development</activity>
  </customState>
  <customState ID="3"
    availability="busy">
    <activity LCID="1033">Onsite at Clients</activity>
  </customState>
  <customState ID="4"
    availability="busy">
    <activity LCID="1033">Meeting with Client - Urgent Interuptions Only</activity>
  </customState>
</customStates>

After creating your .xml file you will also need a .reg (registry file) to merge onto each computer using the custom presence state. the reg file is as followed;

Windows Registry Editor Version 5.00
[HKEY_CURRENT_USER\SOFTWARE\Policies\Microsoft\Communicator]
@=""
"CustomStateURL"="https://fqdn/Presence.xml"
"EnableSIPHighSecurityMode"=dword:00000000


LCID stands for Location ID, you can refer here for a full list.
Issue the following command to enable the Custom Presence:
Get-CsClientPolicy | Set-CsClientPolicy–CustomStateURL “https://fqdn/customstates.xml”
Install .reg file on client computer, when the user signs out and in, the custom Presence can be set

Troubleshooting:

Make sure you can easly view the customstates.xml file from a web browser both internally and externally, if you cant, confirm correct DNS settings for your webserver.

Also make note in the above example there is no "away" custom status. This is not available in custom presence.