Microsoft defending its related Office Web Apps from the search giant’s pitch. In a blog post, Alex Payne of Microsoft’s Online Product Management team disputed Google’s contention that businesses should skip the Office 2010 upgrade by supplementing their existing versions with Google Docs instead. “They’re claiming that an organization can use both (Office and Google Docs) seamlessly,” writes Payne in response to Google’s post. “This just isn’t the case.” As evidence, he offers up the accompanying video, showing a loss of features such as watermarks in the transfer from Office to Google Docs and back again. Microsoft says it has built Office Web Apps to preserve that “fidelity” when making the shift from desktop to online collaboration and back again. We’ve touched base with Google to see if it wants to respond.