Hi Jan, and welcome.
TL;DR: No
Long version:
According to the manual I posted, only the top section should be adjustable:
However, these color settings aren’t there when I want to build the desired embedded url 
Now, in the example url
I found a setting for, what I guess, background:
&bgcolor=%23ffffff
Like this:
But unfortunately it doesn’t make any difference when I try it with several HTML color codes 
