Querying the element with the entwine upload config by class doesn't work because there is also an <input> tag with the same classes on it.

$('.ss-assetuploadfield') OR $('.ss-upload') returns both of these:

<div id=​"AssetUploadField" class=​"field upload ss-upload ss-assetuploadfield nolabel">
<input id=​"Form_getEditForm_AssetUploadField" name=​"AssetUploadField" class=​"upload ss-upload ss-assetuploadfield nolabel ss-uploadfield-fromcomputer-fileinput">​