Ship method for internal sales order

Hello,

We have set up a Transfer From sourcing rule with ship method intransit time (say X days) for an item. ASCP plans correctly using this sourcing rule. However, when we release the planned order to create an IR/ISO, the ship method intransit time on the internal sales order always takes the default one (say Y days) defined in the shipping network. Any pointers on how to make the internal sales order look at the ship method on the sourcing rule?

Cheers!