Parameters must be a list of semicolon-separated key value pairs (e.g. foo=bar;bar=foo) which will not be not trimmed, t.i. foo=bar is not equivalent to foo= bar. Be aware that the equal sign (=) is used to separate keys from values and hence cannot be used in the parameter's value (e.g. if your parameter key is foo and its value is bar=baz using foo=bar=baz will not work).
NOTE: For some pages to work correctly you will also have to tamper the Request-Headers such as the http-referer. See Tamper Data for more information.
