&:: referencing scope resolution operator

[markus3000]

With builder XE5 update1, there is a template class:
template <class T, const IID *piid = &GUID_NULL > /* NOTE: The IID parameter is for backward-compatibility*/
class TComInterface
...

where there is an ambiguity error for GUID_NULL (there is ::GUID_NULL and Oledbc::GUID_NULL)

but adding scope resolution operator here like
template <class T, const IID *piid = &::GUID_NULL >
or even
template <class T, const IID *piid = &Oledbc::GUID_NULL >

does not help (same error)

any ideas?