prioritizing helm keybindings

Hi all,

I'm afraid that's more of a question about elisp than helm proper. But
any suggestion pointing me towards the right direction is more than
welcome.

Some of my helm shortcuts (e.g., C-z for persistent action) got
overwritten when I'm searching with helm. One alternative of course is
to simply define my keybindings so that it doesn't conflict with helm
keys. But what I'd like to check with you guys is the possibility of
another way around. That is, I'd like the helm keybindings to always
have priority when I'm searching with helm.

Given my lack of lisp skills, I could only think of two ways of doing
that. Define a wrap function for helm functions in which I disable the
keys that conflict with helm. That works, but that's very hackish (and
I would have to define a wrap function for every helm function I use).
I thought of using `add-hook 'helm-mode-hook' but I didn't find such a
hook after greping helm source files. But I wouldn't be surprised if I find
out that I simply missed it :)

With minor modes, I know that it's possible to play with the variable
`minor-mode-map-alist' with defadvice so that you can prioritize the
keys from a minor mode. But I couldn't make that work with helm either.

Any suggestions?

Thanks!
mak