Upload a file attachment in Infopath form

In InfoPath form, there is an attachment control for uploading file attachment. But it is recommended by an article in this forum that the file size should not be more than 4MB. For the K2 projects I am working on, if users upload files(10MB), it will cause problems and K2 might run out of memory.

So we need to change the upload feature to upload the files to a file system and only save the link to the uploaded file in the InfoPath form.

InfoPath form does not have a file explorer control. How can I implement this?

I can add a hyperlink, when click it, it will open an aspx page to upload files. But I don't know how to pass the uploaded file locations back to the InfoPath form to save them.

Thanks for your help
coenw