Nvidia connector compatibility

Hi, 
We used to have many precision 7920 rack with 3x Nvidia Tesla P40 (250w tdp) each installed. The P40 Used the old nvidia connector 2x8Pins, the cable from dell shipping with the rack, the 0TR5TP worked fine. The cards beeing well below 300W each and with 2x 1600w PSU, we had no problems. 

We have upgraded the GPU's to 3x RTX PRO 4500 Blackwell (200w tdp), they use the new power connector 12VHPWR, They also ship with an adaptor : 12VHPWR to 2x8 Pins. 

However just pluging the 0TR5TP into the provided adaptor does not boot the card . The card needs 2 separate cables each to boot. Each cable beeing connected to a different 12v rail. Meaning now every server can only have 1 GPU instead of the 3 expected. 

Question : 

Given the RTX 4500 Blackwell uses a 16-pin (12VHPWR) connector with:

• 6 × 12 V pins

• 6 × GND

• 4 × sense pins (S1–S4)

1. Is there a cable that allows directly from 7920 MB/riser GPU power connector to GPU that works with the New NVIDIA cards ? My understanding is that the pins S1 and S2 should be grounded to have the card "sense" it can boot and draw 300w ( 225w + 75w) 

2. Is there an alternative way/ adapter to get the power from another source if (1) is not feasible ? eg external PSU with power cable directly into the GPU 12VHPWR connectors.