Valid W3C XHTML Code?!

Hi there,

i was just asking myself what i can do get my ruby site valid to the w3c
specs. my biggest problem is the auto-generated html code of the link_to
function which gives the form field an id value which includes an array.
that rises the following error:

Line 45 column 20: character “[” is not allowed in the value of
attribute “id”.
<input id=“guestbook[timestamp]” name=“guestbook[timestamp]” typ […]

some ideas what i can do about that (besides write the fields by hand)?

thx in advance