Storage is explained in the second paragraph of the first page of the datasheet
http://www.ti.com/lit/ds/scbs211b/scbs211b.pdfHave your external circuit drive one side or the other to the value you want to store, then assert both output enables (OEAB high and /OEBA low). Then you can tri-state your external circuit, and the transceiver will hold the value.
You end up with two devices driving the bus in between asserting the output enables and tri-stating your driver, but that's OK as both will be driving the same value.
What it can't do is store data while the bus on either side is driven to different values ("even when A data changes"). That will make either it, your other driver, or most likely both, very unhappy.
A small CPLD might be your best option, if you need it bidirectional and able to store data while the input side changes.