It should work fine (DS50 and DS125) with and Ikelite housing as long as they are both DS strobes. I shoot a DS125 and DS50 on another Ikelite housing with a Dual Cord. Have had equipment issues, but otherwise it works.
Also you may want to drop Ikelite a quick email to make sure nothing has changed. 99.99% sure nothing has changed, but once in awhile things do get switched up and worth confirming just in case. As long as they are DS Strobes built after Setpember 2004 it should be fine. Pre September 2004 strobes may have issues.
DS-50 Substrobes
* SubStrobes with Serial Number below 63,850 can NOT be updated to operate correctly with the latest TTL conversion circuitry.
* SubStrobes with Serial Number between 63,850 and 69,999 require a $100 update to operate with the latest TTL conversion circuitry.
DS-125 Substrobes
* SubStrobes with Serial Number below 2,500 can NOT updated to operate correctly with the latest TTL conversion circuitry.
* SubStrobes with Serial Number between 2,500 and 4.999 require a $100 update to operate with the latest TTL conversion circuitry.