it works in Constant contact, however there are no options to change the text or icon, as well as the button color doesn't match the site buttons and is visually unappealing. Buy this if you don't care how it looks or that you can't change it, it does work though.
posted on 8/10/2011
You can change the image button in admin -> languages section.
Please Go to Admin Tab-> Languages -> Local Resources -> Desktopmodules -> cDNN.ConstantContact -> App_LocalResources
-> Select ConstantContact.ascx -> In the Resource Name: Template.Text box, change image button src path to your image path to show your image button.