How to set a tooltip for the image in thee ObjectPageHeader

Hello,

I try to assign a tooltip to the image but it takes default image tooltip ignoring mine. Here is my code:

<ObjectPageHeader id="idUAdetailPageHeader"

objectImageURI="sap-icon://employee"

objectTitle="{Anred} {Namev} {Name1}"

objectImageShape=""

objectImageAlt=""

tooltip="test"

objectSubtitle="{Susid}">

</ObjectPageHeader>

The tooltip shows "Employee" tooltip value. Please advise how can I assign customized tooltip.

Thanks,

Yan