Has anyone had success in using a Diamond Suite Upgrade at this property when combined with the Welcome Credit rate?

I recently booked a stay and wanted to apply the upgrade and was informed by that this rate was not eligible:

Thank you very much for your email with regards to the possibility of utilising a Diamond Suite Upgrade Certificate in our hotel for your upcoming booking in December 2011, paying the 5-night Welcome Credit rate.

We seek your kind understanding that Welcome Credit rate is not an eligible rate for redemption of the Diamond Suite Upgrade Certificate.


This is despite the Gold Passport T&Cs clearly stating:

Suite upgrade is valid on paid nights, for a maximum of 7 consecutive nights; excludes Hyatt Regency Kyoto, Hyatt Regency Paris-Madeleine, Park Hyatt Sydney, Park Hyatt Beaver Creek Resort and Spa, Hyatt Place, Hyatt Summerfield Suites and Hyatt Residence Club Resorts.