You can use Mutt to receive and send email on the HCoop server. However, in order to use Mutt, you have to set it up for working with the Maildir format; add the following to your .muttrc:

set mbox_type=Maildir
set folder="~/Maildir"
set mask="!^\\.[^.]"
set mbox="~/Maildir"
set record="+.Sent"
set postponed="+.Drafts"
set spoolfile="~/Maildir"
mailboxes `echo -n "+ "; find ~/Maildir -maxdepth 1 -type d -name ".*" -printf "+'%f' "`
macro index c "<change-folder>?<toggle-mailboxes>" "open a different folder"
macro pager c "<change-folder>?<toggle-mailboxes>" "open a different folder"