Question Placeholder disappear when insert a logo using a PPT Add-In

[kuli]

Hello,

I've build a PowerPoint Add-In using VSTO which insert logos on a slide in a pre-defined position. Nothing extraordinary...

Here is the poc in charge of doing the insertion :

With Globals.ThisAddIn.Application.ActiveWindow.Selection
      .SlideRange.Shapes.AddPicture(FileName:=fileName, LinkToFile:=Microsoft.Office.Core.MsoTriState.msoFalse, SaveWithDocument:=Microsoft.Office.Core.MsoTriState.msoTrue, Left:=leftPos, Top:=topPos).Name = "Logo"
    End With

My problem is the following : If there is a placeholder (Slide Master/Insert Placeholder/Content), the logo is correctly inserted but the placeholder disappear ! Note that it's produce only if the placeholder is empty before the insertion. I would insert my logos and keep the placeholders in place. Any ideas about that ?

Thanks a lot in advance !