If you want or need caching, you will have to implement it yourself. There are no mechanisms to cache the results of web service calls automatically in ADF Mobile for the time being.
What you need to do is to use the local SQLite database as a cache. Simply wrap you web service calls in a managed bean, and add the code to read/write to the database.
I have one more doubt. In ADF Mobile, Because of performance issue, i want to cache AMX pages also in ADF mobile. Means when user navigate back to the earlier requested page, it will show the data from cache. It will not execute the bean execute method (So no web service call).