Philips DECT phone Phone Book missing in GAP mode

I've got new DECT Philips XL 495 (XL 490) phone as a gift. When I connected it to base from another Philips model (CD 445) in GAP mode, few important options like phone book, call list, option to change date and time did disappear from phone menu. Over a dozen past years I connected a lot of DECT phones (mainly Philips) using GAP profile and I've never experienced any thing like that. I understand that option like access to automatic voice mail are deactivated in GAP but Phone book is a basic function which should always be available. I contacted with Philips support and after long conversation they told me that MISSING PHONE BOOK IS NOTHING UNUSUAL IN PHILIPS PHONES WHEN USING GAP MODE. This way Philips phones in GAP mode has less functionality than DECT phones made 20ty-30ty years ago! :)