How to know if attachment is a signature in an Outlook email

I have an Outlook email and i need to process it's attachments. But when iterating thru the attachments, if the attachment is a signature i want to skip it.

To know if the attachment is a signature i am using:

outlookMailItem.Attachments[i].PropertyAccessor.GetProperty("http://schemas.microsoft.com/mapi/proptag/0x3712001E");

But i am getting an Outlook security alert.

Is there another way using a safer code? Can it be done using Redemption?

Thank you for your time.