Hmm, you seem to be confusing ideas here.
There is no such thing as broadcasting data such that ALL WiFi devices can see. WiFi devices need to cluster togather into groups, and they ONLY see what the group shares.
If you have your iPad connect to the Wi-SP in ad-hoc mode, then your ipad loses its "infrastructure" connection to your main WiFi and the Internet. Maybe that's what you want.
Searching google for "ipad wifi adhoc" will get you instruction on how to convert the ipad to use adhoc wifi.
Search for "digi wisp adhoc" will find you instructions to setup the WiSP. The Digi hardware manual for SP and WiSp should also have the instructions.