Texas Instruments is not DELL.
The quite cheap adapters will blow up your dell frying everything or do nothing at all.
USB Signals are 5v and Firewire are 12v. Plugging 12v into a 5v device will not end well.
The dell community forum is not for support of 3rd party software or hardware.
Other than the Pixela Device there are no USB to firewire Devices in existence.
A reviewer on Amazon UK states that this Startech Firewire card with video editing software works well with the 530s.
Amazon However says:
This product is not currently offered by Amazon.co.uk because a customer recently told us that the item he or she received was not as described.
We are working to resolve this as quickly as possible. In the meantime, you may still find this product available from other sellers on this page.
Have ordered the product though - if it is unsatisfactory the Bay will always accept items back ~ that's the good thing about Customer Support - if you present a clear-cut case; and anyway it is in the vendor's intrerest to attract favourable ratings. Fingers and toes still firmly crossed though 😉