It was mentioned a few pages back. But seeing as I have time I will post it here:
In the ini file place:
HelmetAppearances=(Id=501,Type=CustomizableType_Helmet,Mesh=(Female="BIOG_HMF_HED_PROMorph_R.PROMiranda.HMF_HED_PRO_Miranda_MDL",bHideHead=True,bHideHair=True),PlotFlag=-1)
CasualAppearances=(Id=500,Type=CustomizableType_Torso,PlotFlag=-1)
Select the out of ship look you want, and take the above as your casual look (you know you picked it if your casual look doesn't change). Save and reload. This will cause the game to load your out of ship look on the Normandy.
Now load up gibbed save game editor. Under toolbox/Head Morph fun stuff, shrink or flatten your head, and under Raw/Player/Appearance/Morph Head/Hair Mesh, delete the entire line. The reason you need to do this is because the game doesn't take into account bHideHead=True,bHideHair=True helmet tags onboard the Normandy. You can also add TorsoAppearances using standard casual wear code instead of NPC clothing code. For example
TorsoAppearances=(Id=513,Type=CustomizableType_Torso,Mesh=(Female="BIOG_HMF_ARM_CTH_R.CTHh.HMF_ARM_CTHh_MDL",FemaleMaterialOverride="BIOG_HMF_ARM_CTH_R.CTHh.HMF_ARM_CTHh_MAT_3a"),PlotFlag=-1)