Here is someone's version for the DD500.
"I have programmed a dual delay path similar to the Keeley Halo - 'halo default' preset on the DD-500. This is kind of a hybrid between the Halo and the TC Electronic Alter Ego V2 "EREC2" setting with the dual switch engaged. This has become my main delay patch on the DD-500.
[EDIT: Fixed errors]
The Expression pedal controls the Delay Level.
Mode: Dual
Time: 379ms (The Keeley uses around 470 to 500ms for the Halo preset)
BPM: q=158.3
note: qtr
Dual Mode: A/B PARA (I think the Halo is series)
D1 Type: Tape
D1 E level: 100
D2 Type: Tape
D2 Time 75%
D2 Feedback: 100%
D2 E level: 100
Feedback: 63
Tone: -15
Effect Level: 50
Mod Depth: 87 (This is heavier modulation than the Halo)
Mod Rate: 68 (^^^^)
Mod mode: Bi-Phase (for stereo, normal for mono)
Direct Level: 100
Input Level: 100
EQ SW: Post
EQ Level: 0db
EQ Low Cut: Flat
EQ Lo.gain: 0db
EQ Lm.gain 0db
EQ lm.q: 1
EQ Hm.gain +6db
EQ Hm.Freq 1.00kHz
EQ hm.q: 1
EQ Hi.gain: -2db
EQ Hi.Cut: 1.60kHz
Lo Damp: 0db
Lo Damp F: 20.0Hz
Hi Damp: -2db
Hi Damp F: 2.50kHz"