Continued Anniversary Sync problems with GMail

I had started a thread a few years back but wanted to bring this up again.  I still have issues syncing anniversary dates to GMail.  When I add an anniversary date in either place (either the gmail site or in eM Client) the date gets erased in both places.  That is, if I add a date on either version of the contact (gmail or eM), then sync, the anniversary date disappears.  Can you help?

I was thinking maybe the fields were spelled different, but then I cannot find the anniversary field in GMail contacts. Did you make a custom field?

I was wondering the same thing. What field in Google Contacts did you use for the anniversary date?