How can I send iOS app to client, for them to code-sign

We have created an iOS app for a client, which we would like them to code-sign and distribute.

What is the best method for this? If I Build and Archive, then Share and Save to Disk (no re-sign), I get the .ipa, as required. My question is how would a client then include their provisioning within this? Sending the code to the client unfortunately isn't an option, as we need to keep the source.

Any help would be appreciated