when using mutlipart from, internal value holders do not load their data
for example, use the capatcha on a multipart form.
it will always gives invalid code as there is no data posted at all
this happens because that interval holders like Capatcha and DataTable are using parameter with special ID
for example a Capatcha with id cap1 will post its value under the parameter name
where 1234567 is a changing dynamic value.
hence there was the need to know these parameters when posting back.
the bug is in the methods that searches and loads the data of these parameters as they just were lokking in the form parameters which are empty in case of multipart from
methods loads interalvalueHolder controls should also look into the fileItemsMap where all parameters of nultipart form is stored.