Hello Jean-marie,
Thanks for your post, for generate client side cache, I think there are two ways.
Frist way is use brower to cache, you can check this post gis.thinkgeo.com/Support/Dis...aspx#25249 for some details. But we don't recommend this because it's too touble to view the whole map manual.
Second way is use
LayerOverlay.GenerateCacheImages(Map1.ZoomLevelSet.ZoomLevel08.Scale, cacheExtent1, Map1.MapUnit);
Try to add TiledWmsLayer into LayerOverlay and generate the cache. The problem of this way is you need to know all the extent.
Also our account rep can contact you for a professional service and cache all the tile for you.
I hope this can help.
Regards,
Gary