Yes, you can embed the cab file inside MSI. Though I suggest this is not good to do, but if you don't have an option and you have to just provide a single MSI, then do like this.
Go to Cabs table and add the cab file in there.
Just click on the row in there in ORCA and you will get a screen where you can enter the Cab name. Suppose you enter your cab name as w2.cab. Now upload your cab file as binary in there. Now go to Media table and make an entry there same as it was coming in transform, but just replace the cabinet column as #Cabs.w2.cab
Hope this helps.

Thanks, the MSI has become larger, so it seems to have the CABs inside. but the install is still looking for the files. Would you please give me a little more detail.
Thanks
Dom

The Sequence number has to be maintained as it was when the cabs were outside. This is very important part. First create the transform as it was with cabs outside. You will get some Sequence number in Last Sequence column. you can also verify the sequence of file added in transform and their last sequence. Verify that this is correct and is not modified by you. If it doesn't work, please put screen shots of media and cab table so that I can verify everything is correct.

If I recall correct; Wise is the only one that uses the Cabs (binary) table to store the internal cabinets.

First check if the Cabs table exists.

If yes; then add the cabs to that table instead of the Binary table. Then prefix the Media.Cabinet column value with "#Cabs.".

If no; then I would suggest the quickest way. Download InstEd (www.instedit.com) which is similar to ORCA but with some nice features. Open the MSI in InstEd, go to the Media table, prefix "#" (Cabinet column) for each entry and then add them to the _Streams table. Make sure the (_Streams table) Name column is the exact as (Media table) Cabinet without the "#" prefix.