You can always stall the execution of the code followed by the uiimport command by storing the output as fields in a structure as follows:
S = uiimport(__);
On a note, there is an additional bug in uiimport that affects the return value method. However, this bug has been fixed for Release 14 (R14).
For previous releases, you can look for the following workaround:
1) Delete $MATLAB/toolbox/matlab/uitools/uiimport.p, where $MATLAB is your MATLAB root directory.
2) Edit the $MATLAB/toolbox/matlab/uitools/uiimport.m file.
3) Change line 493 of the uiimport.m file from
out.(vname) = ad.datastruct(names{i});
to
out.(vname) = ad.datastruct.(names{i});
by adding a period between "datastruct" and "(names{i})";
4) Exit and restart MATLAB.
Hope this helps.