MDAC install and nopey

[jsbach]

i need to install mdac in silent mode. mdac must be installed with administrators rights so i'm using nopey addin with runas option. mdac version is checked and if necessary mdactyp is executed directly from inside the main nsis script which is actually installing my application.
the relevant part of the code here:

nsExec::ExecToStack /TIMEOUT=5000 '"$INSTDIR\mdac_typ.exe" /q:a /c:$\"setup /qn$\"'

(note: i choosed nsexec because ExecWait doesn't work well).

MDAC installation is correctly launched and it runs silently upon completion; the problem is that the main scripts goes on without waiting for mdac setup completion.
I believe that nsExec is waiting for 'mdac_typ' execution while the 'real' process to be waited for is 'setup' which is inside the mdac package.

i can't unpack mdac_typ and launch nsexec......'setup /qn'
because too many files inside mdac package; in addition, mdac can run other sub-setups inside depending on system settings.

Any idea on how to get rid of this situation ?
note that the main script (which calls mdac) is launched by another small loader which uses nopey to get administrator rights:

File /oname=$R0 "${NSISDIR}\contrib\nopey\nopey.exe"
nsExec::ExecToStack '"$R0" runas
localadmin:adminpwd "myapp.exe"' ('myapp.exe' then launches mdac if needed).


thanks in advance.