Mobility Security in Exchange Server 2013

Dear Experts,

I just implemented Ex2013 and standard CAL, I have some requirement from user below.

1. He would like to control email in smartphone, how to. Please suggestion

2. He will give user can use mobile access mail via OWA and Smartphone. How do I control OWA to protect Information leak, and how do I control Exchange ActiveSync. and I saw my partner company use encrypt device when use mail in smartphone, I would like how to do it.

3. What's the wipe device? How to? and Benefit?

4. If user attach file that has virus in OWA, can Ex2013 warn or do anything? how to protect it

5. From No.4, How about SmartPhone and Outlook client?

6. What's the Retention policy? It's security feature. Why benefits?

Thank you for your suggestion.