Converting BDN XML subtitles ( + 8-bit PNG images) to Blu-ray-compatible SUP?

[Daiz]

Okay, so I have a BDN XML and 8-bit PNGs to go with them and I'd like to convert them to BD-compatible SUP files (for use with TsMuxeR) without using horribly expensive Blu-ray authoring software like Sonic Scenarist.

Is there any way to do it? I have tried with Sonic Scenarist too, but gave up because I would have had to make a whole BD-disc with it when I only wanted to make SUPs so I gave up with it. And I would prefer free software to begin with.

Example of BDN XML:

<?xml version="1.0" encoding="UTF-8"?>
<BDN Version="0.93" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="BD-03-006-0093b BDN File Format.xsd">
<Description>
<Name Title="English" Content=""/>
<Language Code="eng"/>
<Format VideoFormat="1080p" FrameRate="23.976" DropFrame="false"/>
<Events LastEventOutTC="01:52:58:06" FirstEventInTC="00:03:39:03" ContentInTC="01:52:58:06" ContentOutTC="01:52:58:06" NumberofEvents="5" Type="Graphic"/>
</Description>
<Events>
<Event Forced="False" InTC="00:03:39:03" OutTC="00:03:41:02">
<Graphic Width="1920" Height="1080" X="0" Y="0">line0001.png</Graphic>
</Event>
<Event Forced="False" InTC="00:03:50:08" OutTC="00:03:53:19">
<Graphic Width="1920" Height="1080" X="0" Y="0">line0002.png</Graphic>
</Event>
<Event Forced="False" InTC="00:04:00:03" OutTC="00:04:04:07">
<Graphic Width="1920" Height="1080" X="0" Y="0">line0004.png</Graphic>
</Event>
<Event Forced="False" InTC="00:04:14:11" OutTC="00:04:16:10">
<Graphic Width="1920" Height="1080" X="0" Y="0">line0005.png</Graphic>
</Event>
<Event Forced="False" InTC="00:04:19:10" OutTC="00:04:22:00">
<Graphic Width="1920" Height="1080" X="0" Y="0">line0006.png</Graphic>
</Event>
</Events>
</BDN>