AddCustomButton failed in CorelDraw x7 Update 1

Hi,

The plug-in developed for CorelDraw x7 x32/x64 version works fine prior to update1. It seems that the function call AddCustomButton fails with this latest update. I am using the new x7 typelib vgcoreauto.tlb and the following code fails:

VGCore::ICUIControlPtr pControl = m_pApp->CommandBars->Item[_bstr_t("Standard")]->Controls->AddCustomButton(VGCore::cdrCmdCategoryPlugins, _bstr_t("Command"), 0, VARIANT_TRUE);  

I have since discovered that, setting the last parameter to VARIANT_FALSE would add the custom button but not as a temporary.

Any idea why this call is failing?

Thanks for your help

Abdo