Sales Tax on auctions - California

We are a new Foundation. We are located in California, which does not grant exemption to sales tax to non-profits. We have had a couple of auctions and have received some items from local retailers to auction. I am confused about the regulations. How do others report the basis for sales tax on tangible items where the donation far exceeds the FMV? My understanding is that the entire donation is taxable regardless of whether the business paid sales tax upon donating and regardless of the significantly lower fair market value. Any assistance would be appreciated.