I would like to setup DEE on my phone system with my mobile phone. Is there anyone that has the instructions on how to set that up. I have a Mittel system 5000 CP version 5.0.4.62

First connect w\ DBP and go to Software License. Dynamic Extension Express needs to say 'Yes'. If it does, then do this:

Go to System\Devices and Feature Codes\Phones. Right-click on the phone you want to activate DEE for and select 'Create Users For Selected Phones'.
You should be popped over to the User section automagically, if not go to 'Users'.
Find the User you just created and go to Associated Destinations. Make sure the Extension, Mobile and Voicemail destinations have the correct values. The Mobile number needs to be just like you would dial it from your desk minus the dial-out prefix (usually 8).
Go to Dynamic Extension Express and you should see 2 steps. The first step should show that a call will ring the extension and the mobile destination for 24 seconds. You can adjust this timer as you see fit. The second step should show yer voicemail pilot number. This is where a call will go after the first step timer expires.
Now click back on the User on the left pane and change the 'Enable Dynamic Extension Express' value from 'No' to 'Yes'. Give 'er a test.