It may not be in the font you are using. If so, you can create your own font (I hate editing pixels!) but it can be done. I did one for the icons I use in watchfaces.
Here's a pic of the icon and what I mapped them to.
Right now, support for extended characters is very limited. You could certainly map the € sign to a custom font as Jim describes. We are currently working on improved character support, and expect to add these changes into a future SDK.
