Zoulas,
Actually what you're seeing is expected behavior. Netshare protects the file on disk, but allows you to "use" it in unprotected form in any application (assuming that your key is one of the keys attached to the netshare-protected file).
When you use your email program to attach the file to an email, this counts as "using" the file - i.e., the email program sees the file in unencrypted form, meaning when the email gets sent, it's as if the file was never encrypted.
There are two ways to address this:
1. The better way is to use our email encryption product to encrypt emails. This way it doesn't matter whether the file was originally encrypted or not - the email policies will make sure that emails get correctly encrypted for their recipients.
2. A more cumbersome solution is to "blacklist" your email application in your Netshare policy. "Blacklisting" means that the application will always see encrypted data - it is excluded by Netshare from the list of applications that will see the transparently decrypted version of the file. This is more cumbersome because you will need to make sure that the recipient's key has been added to the file before attaching it. Our email product will provide more transparent protection.