Red Brackets arround my stamp signatue

Hello,

Following code inserts my stamp signature on the right spot but I don't like the red brackets that appears on the side of it...

this.addAnnot({page:1, type:"Square",rect:[108, 189, 216, 212]});

this.addAnnot({page:1, type:"Stamp", AP:"#CrU_odY8ZTF7uTZ0lRBAgB", rect:[108, 189, 216, 212]});

I have played by adding/subtracting 5 to X axis of coordinates of the addAnnote Stamp like:

this.addAnnot({page:1, type:"Stamp", AP:"#CrU_odY8ZTF7uTZ0lRBAgB", rect:[103, 189, 221, 212]});

Did not help at all... how can the Rectangle have no color border?  or... any other suggestion?

Regards,

Jeff P.