5D mkII and YS-D1

I have recently purchased a canon 5d mark 2 with the sea and sea Mdx housing. I have been using 2 YS-D1 strobes for a while with a digital camera but as I have now upgraded I have bought a dual sync cable to use them together with my mark 2. However when I connect them to the housing with the dual sync cable they never flash. I have my mark 2 in flash mode and I can't figure out why this won't work. Can anyone please help? I used a single ikelite strobe for a while and this worked fine

In the menu of the 5d set the flash mode to manual then set the YS-D1 to no preflash

The setting Auto could work with pre-flash (but is useless as you don't have a TTL converter)

Shutter speed should be 1/200 or less or it won't sync

You sure you're using the right cable, with the right bulkhead on your housing? I have a Mk III in an Aquatica, but have a Nikonos bulkhead, going to Ikelite strobes. The pins LOOK similar, but are not.