I would like to know if there is a bug in SFV2.1 that displays ArcIMS Services (9.3.1) shifted. You can test that at following link (a demo): http://iderm.imida.es/demo2
The ArcIMS service is named 'srs4258' (in tag 'Otros mapas'). Every layer in this demo has the same SRS, that is, SRS4258.