[Connect C# Addin] How can I get my own icon to a button on a ribbon?

How can I get my own icon to a button on a ribbon? Do I need a icon resource?

The Ribbon is load to Microstation Connect Edition and works fine. I use a xml file for the ribbon. Here is a snippet of a button in the xml file.

    <Button Name="MSCEAddin.OpenAction" Priority="100">
      <Label>Open</Label>
      <Description>Open document.</Description>
      <ButtonParams CollapseToSmall="WhenGroupIsSmall" Size="Large">
      </ButtonParams>
      <ButtonData>
        <CommandData Type="UserKeyinCommand">
          <UserKeyinCommand>
            <Keyin>MSCEAddin Open</Keyin>
            <Icon Type="NamedIcon">
              <NamedIcon>Application</NamedIcon>
            </Icon>
          </UserKeyinCommand>
        </CommandData>
      </ButtonData>
    </Button>

I think, the issue is the NamedIcon <NamedIcon>Application</NamedIcon>. How can I get 'MyOwnIcon.png' as icon?