Welcome! The guys on the Toy Hauler forum here speak highly of Poles & Holders, have you looked at their mounts? They do make a ramp door mount that might work.
*click here*This thread on the Toy Hauler forum might be good help, some custom holders with photos.
*click here*If you didn't know about the Toy Hauler forum it's just down the list a bit, might fine some good info for your WW.
*click here*
Two Wire Fox Terriers; Sarge & Sully
2007 Winnebago Sightseer 35J
2020 Jeep Gladiator Rubicon