How to Send Custom URL link via Email not in Gmail.

Hi I am strugling this part of work: i need to send custom URL link via Android device Email not via Gmail. Am using below code this code workin well in Gmail but not working in Email option..

var var1 = "sss";
            var var2 = "ppp";
            var emailDialog = Titanium.UI.createEmailDialog();
                emailDialog.subject = "Some Subject";
                emailDialog.toRecipients = [];
            var ch ="<a href='Myapp://?var1="+var1+"&var2="+var2+"'>Click Here</a>";
                emailDialog.messageBody = "Download My and "+ch+" to open it";
                emailDialog.setHtml(true);
                emailDialog.open();

The "Click Here" i want to change url link option like. Please Give your ideas for my doubt.