My mistake. It's not a Bosch, but rather a Trek product/part number -- marketed as "Trek Allant+/Diamant Zouma+ Battery Spacer". Sorry for any confusion.
Bosch does make an adapter specifically for this. BTRYPT EBK 500-625W SPCR Part No W582323. Don't know how widely available it is. You might try a Trek dealer if your R&M dealer can't help.
