found the trick! here is how to do it (in case somebody else has this issue):
from the CLI run
wget -r --level=2 http://nameoftargetsite
then make sure that no non htm/html files have been downloaded (I had a few zipped one).
Next, find the exact page which has the URLs of the files on the remote site. Point caliber to that very same page on the local machine and import it.
Finally, convert the book into EPUB , FB2 or any other format :-)
HTH!