file attachments in mail sending

file attachments in mail sending

hello
ive shared my app to support edit
thats my app
http://creator.zoho.com/talamit/app
ive created the formula and send field as listed in the forums.

that's my forumla
("<a href='http://creator.zoho.com/DownloadFile.do?filepath=/" + File_Upload + "&sharedBy=" + zoho.adminuser) + "'> קובץ לדוגמא </a>"

this is my send dcript
no matter i send a file or not, i have a "null" written on my mail.
please explain me how to fix it.
so, when there is no file uploaded the person who receives the mail will see nothing, and when there is he will see the linked attached.
p.s ive tried to have my signature written colored by adding <div text color="ff0000"> </div> around it , but it didnt do anything.
thanks for the help
tal
talamit