External PERC 8 multipathing on VRTX - only one path available

I have internal and external PERC 8 cards in fault tolerant mode on VRTX

Internal PERC - presented VDISK (internal storage) to VMware - can see 2 paths

External PERC - presented VDISK (on MD1220) to VMware - can only see 1 path.

Is this normal behaviour for External PERC as I would expect to see 1 active and 1 passive path (ie 2 paths) the same as what I see for the internal PERC.