Hello,
these drivers have to supplied by the manufacturer of the hba. Tekram doesn't supply SPARC drivers.
Even if you can locate a third-party (SPARC) driver that someone has written, this card isn't supported by the OBP (and contains no OpenFirmware). That means you can't attach the boot disk to this hba.
I would recommend that you get a 53C875 based card instead.
Unfortunately the Tekram DC-390F which uses a 53C875 works only at the ok-prompt (the glm driver doesn't attach).
EDIT: When comparing the .properties of the DC-390F and SYM8751SP, the only difference is the revision-id. The SYM8751SP uses revision 4 while the DC-390F uses revision 3.
The SYM8751SP(E) works. It's directly supported by the OBP and at the os level.
Michael