When editing your signature just put the following in front of it (but take the spaces out between the brackets and letters.)

[ hr ]

Here is an example...  I'll place this in front of my name to finish this post.. and I mean right in front of your signature... dont hit enter or anything (remember take the spaces out)

This is an example of how I would do it... but I put spaces in so the line doesn't actually show up.

[ hr ]Bare

and here is how it looks... with the spaces removed.