I a not actually quite sure if i got you correctly or not.
when i run the program in vmware or vbox, it went fine. without plugins, it just keeps throwing memory violations which i am assuming due to detection of the debugger . unpacked file runs without a hitch.
When i installed fresh virtualpc , it resulted similar as before(all went fine).
Now , i manually set the trap flag by writing a small codecave and disabling "pass exception to application" . It reaches the exception and olly notifies me .
Code:
pushfd
pop eax
or eax, 0x00000100
push eax
popfd
With my limited knowledge i couldnt do much more than this .
So my assumption about the failure to handle single steps is that somehow you messed up hardware virtualization support or something similar to it . Earlier versions of virtualpc for windows 7 didnt support software virtualization till they released a patch to enable it. if that is the case , you need to enable hardware virtualization to solve the issue probably.
second case may be improper plugin settings.
Let us know the result of this issue.
Cpu used was i7 4770k .