Set Password For Active Directory Lightweight Services

I am trying to create a new user and set their password in AD LDS using asp.net vb. I'm binding to an instance of a directory entry, which is working fine. And I can add a user without a problem. The problem is that I can't seem to set the password when I add the user. Is this the right way to set the password?

Dim objADAM As DirectoryEntry = BindToInstance()
Dim objUser As DirectoryEntry = objADAM.Children.Add("CN=Jimmy", "User")
objUser.Properties("sn").Value = "lloyd"
objUser.Properties("givenName").Value = "Jimmy Smith"
objUser.Properties("userpassword").Value = "THEPASSWORD"
objUser.CommitChanges()

This is the error that I get :
System.DirectoryServices.DirectoryServicesCOMException (0x80072020): An operations error occurred. (Exception from HRESULT: 0x80072020) at System.DirectoryServices.DirectoryEntry.CommitChanges()

I've also tried this :
Dim objADAM As DirectoryEntry = BindToInstance()
Dim objUser As DirectoryEntry = objADAM.Children.Add("CN=Jimmy", "User")
objUser.Properties("sn").Value = "lloyd"
objUser.Properties("givenName").Value = "Jimmy Smith"
objUser.CommitChanges() objUser.Invoke("SetPassword", New Object() {"123456789A$#"})
objUser.CommitChanges()

Which gave me this error :
System.Reflection.TargetInvocationException:
Exception has been thrown by the
target of an invocation. --->
System.Runtime.InteropServices.COMException
(0x8000500D): The directory property
cannot be found in the cache. --- End
of inner exception stack trace --- at
System.DirectoryServices.DirectoryEntry.Invoke(String
methodName, Object[] args)