Hi Suresh,
Refer to Page 18 to see that save for offline viewing option is available under Share option. try accessing BI content from IPAD first to find the options in easy way until you get familiar with options in app. you can also try Add to home option by tapping the document Info icon, to save the reports and show on home page.
http://help.sap.com/businessobject/product_guides/boexir4/en/44x_mobiOS_user_en.pdf
Unfortunately, I do not have mobile app connectivity right now, could have pointed with the exact steps other wise.
Thanks
Mallik