Pass parameters from activities pane to activity form

I need to implement SMS module as activity entity, and I followed the below link and implemented successfully but I can't submit the customer details (Name/Id, Phone Number) as parameters to SMS activity form, please advise for a solution.

http://www.furnemont.eu/2011/06/07/how-to-series-send-sms-messages-from-crm-2011-part-3/

Needed solution likes the below