Thread Subject: Map layers question

My code for displaying gridded data (e.g., SST) on a global map has previously worked just fine on earlier versions of v7. I recently upgraded to R2009b (v7.9.0), which has not previously given me trouble with any other applications of it, but I just ran the map code for the first time and I have a strange issue with layers. Normally (previously), layers on a map were displayed bottom-up in the order that they were made (i.e., the first layer made, is the bottom/back layer, and the last layer made is the top/front layer).

Here is the map part of my offending code:

h1=worldmap('world'); %load the global map axes
mstruct = getm(h1); %get the map handle incase needed later
mlabel('off'); %turn off meridian (lon) labels
plabel('off'); %turn off parallel (lat) labels
[lat,long]=meshgrid(-88:2:88,0:2:360);
R=makerefmat(-1,-88,2,2); %make the reference matrix
geoshow(gridded_data,R,'DisplayType','surface'); %throw the data on the map
[c,h]=contourm(lat,long,gridded_data,'-k');
L=geoshow('landareas.shp', 'FaceColor', [0 0 0]); %plot continents

Ideally, this should generate global map axes, and then makes a first (bottom/back) layer that is the gridded SST. Next, it contours that data. Finally, it throws the continents ('landareas.shp') on the top of everything so the coastlines are neat and not cropped oddly based on the gridded data.

For some reason, this layering works just fine in the southern hemisphere where there is negatively valued data (blues and greens), but the gridded data is the top/front layer in northern hemisphere where there is positively valued data (reds), obscuring the bottom half of Florida (for example), and covering the contours. Note that in the arctic, where values are again negative, the contours reappear.

Any help on this matter would be greatly appreciated. Thanks!