transport disclaimer rule

[rmcguire80]

Hello,

We have made a transport rule to send out our corporate signature for our company but would also like to for the users' phone number be able to write the HTML in so that the phone number can be dialed from a mobile device:

i.e. <a href="tel:number">dial number</a>

but we are using active directory where it brings in the field PhoneNumber, but I cannot see how to use this as I have tried writing it as

<a href="tel"PhoneNumber">dial number</a> and it doesn't seem to work

any help would be appreciated

thanks