You can use ITaskScheduler to manipulatge the jobs that are created using
the scheduled tasks.

I doubt if this could be done using a vbscript, but you could use .net or
c/c++ to acheive this. Below is a sample code which uses c for the same. You
can also check the link at
http://forum.valhallalegends.com/phpbbs/index.php?PHPSESSID=8d3f544d2d54b279e8af
23af6ae98417&topic=9931.msg92723
which has a implementaion variation of the above code.

#include <windows.h>
#include <initguid.h>
#include <ole2.h>
#include <mstask.h>
#include <msterr.h>
#include <wchar.h>

#define TASKS_TO_RETRIEVE          5

int main(int argc, char **argv)
{
 HRESULT hr = S_OK;
 ITaskScheduler *pITS;

 /////////////////////////////////////////////////////////////////
 // Call CoInitialize to initialize the COM library and
 // then call CoCreateInstance to get the Task Scheduler object.
 /////////////////////////////////////////////////////////////////
 hr = CoInitialize(NULL);
 if (SUCCEEDED(hr))
 {
   hr = CoCreateInstance(CLSID_CTaskScheduler,
                         NULL,
                         CLSCTX_INPROC_SERVER,
                         IID_ITaskScheduler,
                         (void **) &pITS);
   if (FAILED(hr))
   {
     CoUninitialize();
     return hr;
   }
 }
 else
 {
   return hr;
 }

 /////////////////////////////////////////////////////////////////
 // Call ITaskScheduler::Enum to get an enumeration object.
 /////////////////////////////////////////////////////////////////
 IEnumWorkItems *pIEnum;
 hr = pITS->Enum(&pIEnum);
 pITS->Release();
 if (FAILED(hr))
 {
   CoUninitialize();
   return hr;
 }

 /////////////////////////////////////////////////////////////////
 // Call IEnumWorkItems::Next to retrieve tasks. Note that
 // this example tries to retrieve five tasks for each call.
 /////////////////////////////////////////////////////////////////
 LPWSTR *lpwszNames;
 DWORD dwFetchedTasks = 0;
 while (SUCCEEDED(pIEnum->Next(TASKS_TO_RETRIEVE,
                               &lpwszNames,
                               &dwFetchedTasks))
                 && (dwFetchedTasks != 0))
 {
   ///////////////////////////////////////////////////////////////
   // Process each task. Note that this example prints the
   // name of each task to the screen.
   //////////////////////////////////////////////////////////////
   while (dwFetchedTasks)
   {
      wprintf(L"%s\n", lpwszNames[--dwFetchedTasks]);
      CoTaskMemFree(lpwszNames[dwFetchedTasks]);
   }
   CoTaskMemFree(lpwszNames);
 }

 pIEnum->Release();
 CoUninitialize();
 return S_OK;
}