@Martial this is answered in the support ticket you submitted. Thanks for sending in the sample scene. In case any body comes across this in the future the solution is subdivision.

The dynamic clothing was subdivided at the preview level. When Poser spawns a morph it only does it for the current level of subdivision. The dynamics only exist at the base level. There's literally no morph that exists on the subdivided mesh ... Yeah it's weird.

Fortunately the fix is really easy. Set the subdivision on the dynamic cloth to 0 before spawning the morph. Then you can set the subdivision back to whatever it was before.

Step:

• Run the cloth sim as usual
• Set Subdivision to 0
• Spawn the new morph
• Reset subdivision to previous setting.

Set Preview to 0 before spawning the morph.