Thank you Vadim, but, sorry, perhaps I have not understand exactly where I have to add "&Source=http://.." in the html code? Perhaps here?:
(where I have add the XXXXXX)
<p class="ntx-rteFontSize-3"><strong>Please click </strong><span id="NWRTEReference_A"><a class="ms-rtestate-write" contenteditable="false" onclick="selectThis(this);" href="BLOCKED SCRIPTvoid(0);" reftext="here" link="true" reflink="{Common:ApprovalUrl}" XXXXXXXX style='color: blue; text-decoration: underline'><strong>here</strong></a></span><strong> to respond to the task.</strong></p>
Thank you very much,
matteo