The connector that you have circled is not needed.
I had SLC working entirely off the slide-in connector.
This is the pinout that I used:

A01	GND
A02	AUI 13 +12vdc
A03	+12  J0201 5
A04	GND  J0107 2
A05	GND
A06	GND
A07	GND
A08	GND
A09	GND
A10
A11
A12	+5    J0107 1
A13	+- ??
A14	Kbd 8
A15	RS A:DSR
A16	RS A:TCO
A17	GND
A18	GND
A19	GND
A20	GND
A21	GND
A22	GND
A23	GND
A24	RS 7
A25	+5    J0107 1
A26	+5
A27	+5
A28	+5
A29	+5
A30	+5
A31	+5
A32	+5 in backpane
A33	SCSI 38 TERMPWR
A34	+5
A35	SCSI 38 TERMPWR
A36	+5
A37	RS A:DTR
A38	+5
A39	RS A:DCD
A40	+5
A41	RS A:CTS
A42	-12V  J0201 6
A43	RS A:RTS
A44	RS A:TD  2
A45
A46	RS A:RD  3
A47	J0201 8
A48	RS B:RTS
A49	RS B:TD
A50	?
A51	RS B:DCD
A52
A53	RS B:RD
A54	J0107 2
A55	RS B:CTS
A56	Kbd 3
A57	Kbd 3
A58	Kbd 4
A59	10KOhm to both Vcc & GND
A60	GND

B01	GND
B02	AUI 13 +12vdc
B03	+12
B04	AUI 9 E.COL-
B05	AUI 2 E.COL+
B06	AUI 6 SGND
B07	AUI 10 E.TD-
B08	AUI 3 E.TD+
B09	AUI 6 SGND
B10	AUI 12 E.RD-
B11	AUI 5 E.RD+
B12	+5 J0201 1,2,3
B13	-"-
B14	Audio 3 (+1Ohm)
B15	Audio 6
B16	RS 16   ???!
B17	RS 7
B18	RS 7
B19	Video center
B20	Video shield
B21	J0107 5
B22	J0107 6,2
B23	-"-
B24	+5 J0107 3
B25	J0107 1
B26	SCSI 33 DB(7)
B27	J0107 1
B28	SCSI 32 DB(6)
B29	J0107 1
B30	SCSI 31 DB(5) 
B31	J0107 1
B32	SCSI 30 DB(4)
B33	SCSI 38 TERMPWR
B34	SCSI 29 DB(3)
B35	SCSI 38 TERMPWR
B36	SCSI 28 DB(2)
B37	+5 J0107 1
B38	SCSI 27 DB(1)
B39	+5 J0107 1
B40	SCSI 26 DB(0)
B41	+5 J0107 1
B42	SCSI 34 DB(P)
B43	J0201 3   pwr?
B44	SCSI 41 -ATN
B45	SCSI 43 BSY
B46	SCSI 35,36,40,42 SGND
B47	SCSI 44 -ACK
B48	SCSI 35,36,40,42 SGND
B49	SCSI 45 -RST
B50	SCSI 46 -MSG
B51	SCSI 47 -SEL
B52	SCSI 48 -S/D
B53	J0107 1
B54	SCSI 49 -REQ
B55	SCSI 50 -I/O
B56	Kbd 3
B57	Kbd 8
B58	Kbd 6
B59	Kbd 5
B60	GND

--Pete