[SalesForce] Embed a Visualforce page in a Standard Edit Layout

I needed to output some text on a custom object and managed to do so by embedding the following VF in the Custom Layout:

<apex:page standardController="Standard_Controller__c">
    <apex:outputPanel layout="block" style=" height: 50%;">
                <apex:outputText style="font-style:italic" value="Test">
    </apex:outputText>
            </apex:outputPanel>
</apex:page>

However, the same VF does not appear in the standard edit page layout. Does it mean that this is not possible?

Thanks,

I.