how can i put this on my signature??? i can't put it..

Find a host for your signature (imageshack.us or tinypic.com), follow their site to upload the picture > Take the URL code they give you when the picture is uploaded and copy it > Come back to UM > Click 'My Controls' on top of the page > Left hand side scroll down to 'Personal Profile' under there click 'Edit Signature' > hit the image button > paste in your image's URL > Click ok and then click 'Update my Signature' button and that should do it.

Any questions, just ask.