[Therion] show only fixed survey point on maps

hello, I'm looking to display the fixed survey points on maps, but I didn't succeed. I try to set the symbol-hide / symbol-show command in the layout bloc, but if I put symbol-show point station I have all the station points displayed (not only the "subtype fixed" points) and if I put symbol-hide point station symbol-show point station:fixed I have no station points. I saw in the manual that we can use flags to show specific stations ( flag:<entrance/continuation/sink/spring/doline/dig> ) But can we use the subtype of the station points to do the same selection ? Thanks Gilbert