In general, those with hard seed coats, e.g. pea family, benefit from scarification. Dr. Deno didn't find that soaking was generally beneficial; it also results in risk of oxygen deprivation. (Yes, I realize that this is a very popular method, with abundant anecdotal claims of beneficial effects. ;-) )
Maybe that's why so many people soak "difficult" seeds in dilute hydrogen peroxide. It adds O2. Of course warming the water drives dissolved gasses out, and they only diffuse back in rather slowly after the water cools.
I forget where I read this, but someone was explaining to commerical growers how to germinate something really difficult, and also get them to bloom. After going through proceedures that sounded like Nobel Prize level work to me, he added something like: "For most hobbyists, BUYING the plant may be a better use of their time".
I really liked a little text "database" that may have started life at Thompson & Morgan, then was made public at Virtual Seeds (http://www.virtualseeds.com/Germination.html) , but that site seems to have disappeared and now leaqds to some search engine.
It was great and concise and easily searched. It had SEVENTEEN categories of special treatments that certain kind of seeds benefited from. But Virtual Seeds said it was "property of Thompson & Morgan" so I wouldn't feel right just posting a copy I took.
The hard seed coat / chipping section suggested scratching or abrading with knife, pin or sandpaper to allow water to pass through the hard seed coat.
Soaking was said to soften a hard seed coat, or leach out any germination inhibitors.
"24 hours in water which starts off hand hot is usually sufficient."
If you soak longer than one day, change the water.
Then they got into cold moist stratification and "Double Dormancy".
And surprisingly sophisticated techniques that move seeds between cold frames, greenhouses and just outdoors.
It has these columns:
Species Type Germ Days Germ temp Media Sow Depth Comments
Ailanthus HT 30-90 L X 50-60 Well drained S Chip, soak then No. 14 for 2 weeks.
"L" for "needs Light" and "S" for "Sow on Surface".
Plus some handy abbreviations for things like "Hardy Tree", "Half Hardy Biennal" or "Greenhouse Perennial".
Plus the ever-reassuring "The "X" stands for slow and irregular germination."
I take that to mean "Maybe I haven't killed them all quite yet".
You might have to look around a little for the najme tbhat matches your plant. They seem mostly to use genus names.