Xrm.Utility.openEntityForm: causing an issue with Outlook Client

Hello,

I have one issue with Xrm.Utility.openEntityForm.

I have created one ribbon button on SubGrid of one of my custom entity.

The custom entity SubGrid is situated on Lead entity.

I have a functionality like on lead record when user select my custom entity subgrid then one ribbon button should be appeared named as Open Email.

When ever user Click on this button, we need to open new record form of Email entity.

So, to implement this I have used Xrm.Utility.openEntityForm

This is working fine in CRM 2011.

but The problem is when I trying execute same functionality from Outlook client then the outlook window display for new record window. but I need CRM window.

Please help.