"Cross Selling" In Service Order

Hello;

Here's my scenario;

I would like to have some sort of "cross selling" in my service orders, Example: My order is usually composed by two items one is a sales Item (physical product) the other one is a Sevice Item (for example the Delivery Time for the product) so in brief

Item Number1 TV

Item Number2 Delivery10 Which means it will be installed in ten minutes.

I would like my customer to have a "cross selling scenario" where once the TV is picked the operator could choose between a Delivery10 Delivery20 Delivery30 for instance.

I tried to assign the cross selling schema as i would do for a sales transaction but even if i can make the assignment i don't see any pop up of sort once i create the order.

Help please

Regards