SVG: Unrecognized image file format

I am using Win10 64bit, vaadin 7.6.8, eclipse 4.6.0.
I am developping a vaadin widget, with gwt and vaadin.
The Widget works.

I have Problems with: GWT-ToggleButton and SVG-Image.
When i want to add a PNG-Image to the GWT-ToggleButton, all works fine!
When i want to add a SVG-Image to the GWT-ToggleButton, i get the error "Unrecognized image file format"!

Here ist what i have coded:
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Im am using a ClientBundle

public interface IconResourcesBundle extends ClientBundle {
    
    public static final IconResourcesBundle INSTANCE = GWT.create(IconResourcesBundle.class);

    @Source("bold.png") 
    public ImageResource bold();
    @Source("edit.svg") 
    public ImageResource edit();
}

The following Code with the png-File works fine

private com.google.gwt.user.client.ui.ToggleButton boldTButton;
boldTButton = new ToggleButton(new Image(IconResourcesBundle.INSTANCE.bold()));

The following Code with the svg-File throws the error: Unrecognized image file format

private com.google.gwt.user.client.ui.ToggleButton boldTButton;
editTButton = new ToggleButton(new Image(IconResourcesBundle.INSTANCE.edit()));

In my pom-file i have added:

<dependency>
            <groupId>org.vaadin.addons</groupId>
            <artifactId>gwt-graphics</artifactId>
            <version>1.0.0</version>
        </dependency>

In my ....gwt.xml i have added:

<inherits name='org.vaadin.gwtgraphics.GWTGraphics'/>

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