DialogMusicInfo.XML missing play button in certain skins ?

I have an addon which pulls video and music files from a uPNP server, creates listitems in Kodi and allows users to play the media.  it does a lot more like populating the Kodi database (i.e. syncing to the uPNP server database etc..).  Up until recently I have focused on the video playback and syncing and all has worked great.  I've recently started enhancing the music section.  Everything is working great except when I click on the Info context menu item which launches the  DialogMusicInfo.xml skin file I am not getting a play button like I do with videos.  If I point Kodi directly at the Kodi music database which is in sync with my uPNP server I get a play button so I know the funtionality works.. 

Here's the data I am sending the skins for music:

info = {
                        'duration': getSeconds(duration_text),
                        'genre': genre_text,
                        'year': release_year_text,
                        'title': title,
                        'artist': artist_text.split(','),
                        'rating': rating_val,
                        'discnumber': season_text,
                        'mediatype': 'song',
                        'tracknumber': episode_text,
                        'album': album_text,
                        'playcount': playcount,
                        'lastplayed': last_played_text,
                    }
                    li.setInfo('music', info)

I am not a skinner but have started digging through the skin code for Confluence to better understand how the skin works..  I was able to manually update the DialogMusicInfo.xml file and add button 8 as a play button and add an onclick action to play the music item but that isn't an approach I would prefer.  Since Confluence works with videos and when I point at music files in the Kodi database, the Play button functionality is in there but I cannot find where in the  skin code.  Oddly, with Estuary I get a play button for both audio and videos but no other skin I have tested presents a play button for music in the DialogMusicInfo.XML file when pulling content and populating my addon listitems. 

I think the issue may be that the my addon isn't sending the Skin something it needs to display the play button but I cannot figure out what. 

Here's the relevant section of code from the DialogMusicInfo.XML file:

                <include content="MusicInfoPanel" condition="String.IsEqual(ListItem.DBTYPE,artist) | String.IsEqual(ListItem.DBTYPE,album) | String.IsEqual(ListItem.DBTYPE,song)">
                    <param name="panel-left" value="340"/>
                    <param name="panel-width" value="900"/>
                    <param name="item-width" value="450"/>
                    <param name="label-width" value="430"/>
                </include>
                <control type="grouplist" id="9000">
                    <left>210</left>
                    <top>660</top>
                    <width>1030</width>
                    <height>40</height>
                    <itemgap>2</itemgap>
                    <align>center</align>
                    <orientation>horizontal</orientation>
                    <onleft>9000</onleft>
                    <onright>9000</onright>
                    <onup>50</onup>
                    <ondown>49</ondown>
                    <control type="button" id="6">
                        <description>Refresh</description>
                        <include>ButtonInfoDialogsCommonValues</include>
                        <label/>
                    </control>
                    <control type="button" id="10">
                        <description>Get Thumb</description>
                        <include>ButtonInfoDialogsCommonValues</include>
                        <label/>
                    </control>
                    <control type="button" id="12">
                        <description>Get Fanart / Album info</description>
                        <include>ButtonInfoDialogsCommonValues</include>
                        <label/>
                    </control>
                    <control type="button" id="7">
                        <description>Set my rating</description>
                        <include>ButtonInfoDialogsCommonValues</include>
                        <label/>
                    </control>
                </control>

I've looked through the includes.xml file at the MusicInfoPanel section but don't see where a play button might be created.  I am hoping one of you can help me out.


Thanks,

Jeff