Is iPad any less secure on my corporate network than an iPhone?

I and a number of people at my are now using iPhones on our corporate network as follows:
- using the corporate wifi network for internet access
- accessing email accounts on the exchange server using the standard iPhone email application.

All of the computers in the company are part of a windows domain and none of the iPhones are members of the domain or are using any windows services, shares, etc. Nor are they using VPN.

I have just purchased an iPad and configured it to use exactly these same 2 services. Now my network administrator is telling me that because it's a "computer", I can't have it on the corporate wifi network because it presents different security risks than an iPhone and may have "open shares". I have tried telling him that it runs exactly the same OS as an iPhone and that all I am doing is using the wifi to connect to the internet.

I have not jailbroken my iPhone and don't intend to jailbreak the iPad. I have the iPhone set up with a passcode and configured to erase all data after 10 failed attempts. I also have find my iPad set up with MobileMe to remotely wipe its data if it is lost or stolen.

How can I reassure him that having a non-jailbroken iPad on the corporate wifi network presents no more security risks than an iPhone and cannot transmit any viruses to networked PCs and can't access any corporate shares or data?

HELP!!!!