multipart/form-data form doesn't work with accordionPanel

[lotka]

I have a problem with accordionPanel from Primefaces. I want to have a tab where user can load a file (it's enctype property has to be set to "multipart/form-data"). The form looks like:

<h:form id="uploadForm" enctype="multipart/form-data" prependId="false">
<t:inputFileUpload id="file" value="#{form.uploadedFile}" required="true"/>
<h:commandButton value="load" action="#{form.saveFileOnDisk}" />
</h:form>

I've tested this form without using accordionPanel and it's working ok. But when I put this form inside the accordionPanel. In saveFileOnDisk method uploadedFile is null. I've tried using Primafaces upload component too. It doesn't work either.
Any ideas?