Set Map Extent with layers with different wkid

[JimBridge]

I have a map with a spatial reference of 102748 (2285) and want to use
http://server.arcgisonline.com/ArcGIS/rest/services/ESRI_StreetMap_World_2D/MapServer as a background layer. This map has a wkid of 4326  (4326) .

Once I've added them I want to zoom to my map with the wkid 4326.

I'm adding the layers   map.addLayers([backgroundMapLayer, LinkedMap]); //      map.addLayers([102748 , 4326]);

What should I be using to the map extent. I've tried using the linkedMap full exent min/max xy coordinate and wkid of 102746.
I've also tried to set it to background min/max xy coordinate and wkid of 4326
I've then tried to zoom the map and get the whole world ( I can manually zoom and center and see my map layer over the base map in the correct place) or 0,0 off of Africa.

If someone could explain to me what I should be setting my initial map extent so when I run  map.setZoom or   map.centerAndZoom(map.getLayer("baseLayer").fullExtent.getCenter(), 5) it zooms to where my map I'd appreciate it.

I'm believe I'm missing how I reconcile the different wkid.

Thanks

Jim

[JimBridge · Accepted solution]

Not sure why it wouldn't zoom but realized the 2d service is on extended support and changed to the world street map and everything worked fine as is.

http://www.arcgis.com/home/item.html?id=3b93337983e9436f8db950e38a8629af

Thanks
Jim