When submitting dialog to Quickblox I add QBDialogCustomData using the code below
QBDialogCustomData qbDialogCustomData=new QBDialogCustomData("UserInfoDialog");
qbDialogCustomData.putString("FBID1", myApp.getFbid());
qbDialogCustomData.putString("FBID2", fbid);
qbDialogCustomData.putString("USERID1", String.valueOf(myApp.getUserID()));
qbDialogCustomData.putString("USERID2", String.valueOf(userId));
qbDialogCustomData.putString("FULLNAME1", myApp.getFullname());
qbDialogCustomData.putString("FULLNAME2", fullname);
dialog.setCustomData(qbDialogCustomData);
However when later using the getCustomData method it returns null, what is missing to submit the QBDialogCustomData, I have the Custom object class created with the right fields so that shouldn't be an issue.