I am designing an email signature for a client, which is a pain in the neck because of limitations of the various email clients and how they behave with HTML.

I have used an html email boilerplate, and all is working well with the signature behaving and displaying on various email clients including Gmail, Yahoo, etc.

The problem I am having is when someone replies to the signature from Apple Mail, everything looks fine except the URLS in the signature get stripped out and displayed.

For example, in the signature there is a link with a href which normally displays as View Products.
On reply from an Apple Mail client, it shows as View Products <http://sitename.com/products>

After examining the source of the reply mail, it has indeed stripped out the href and placed it next to the link text.

Any ideas of why this happens, and is there any way to prevent it?