Can BSP iViews be used in externally facing portal in EP6?

We have developed BSP applications and set them up as iViews in EP6. Our portal implementation will be used by external users.

We have security concerns that the access to the BSPs via the portal allows external users direct access to the R/3 system. We were told that we should use ITS application instead of BSP.

Do any of you have any insight into how we could work around the security problem with BSP applications in EP6? Your help will be greatly appreciated.