Quickform - order of applyFilter() and addFormRule() ?

Hello, I use a custom validation rule function. My question is, what is the order of precessing QF goes? a) fixed order? 1) assign filter 2) check custom form rule / rules b) depends on the order you code it? I change a filename, to make it save to be written to a filesystem. But I want to verify this new name is not already used. So far my rule function works, but it seems not to use the *filtered* submitted value ...? -- christian luszick