And yes, as a catechumen, I believe, you cannot partake in the Holy Mystery of Confession. I wanted to confess my sins when I was a catechumen (in winter 2007), but my priest said, wait until you are chrismated, because right now the confession will not have any sacramental value anyway. When you are chrismated, you are a member of the Body of Christ, and then you can (and should) partake in the Holy Mystery of Penance (or Confession).
Just curious... I am aware that some traditions require a lifelong confession of sins prior to one's baptism/chrismation, so I'm not sure how accurate your statement is.