Dreamweaver does not allow hyphenated word

Hi,
I was wondering why Dreamweaver doesn’t allow hyphenated words in a page; words like mother-in-law, etc.
It converts to motherinlaw which is definitely wrong, right.
Is this a known bug in Dreamweaver?
If so, is there a workaround for this?
Please help. Need this ASAP.
See screenshot of error message:

Error:
Dreamweaver
Names can only contain low-ASCII letters and numbers and cannot begin with a number.
