Maintenance Scheduler

Morning guys and gals

I am trying to create a sceduling calendar for my department which displays given events day by day.
I have created this using subforms for each day and a combo box to select the month.
For display purposes it works fine but I am having a little difficulty with the functionality.
I want to be able to click into any of the subforms, and depending on whether there is data within, open a specific document.
1)If there is an item in the schedule the I want to open a report filtered for that date.
2)If the day is blank then I want to open a form to input an item. (This works but I cannot get the date to pre-fill)
I have created a seperate piece of code to do this but it doesn't want to work. It may be because my knowledge of VB isn't what it was or it may be that I am completely barking up the wrong tree.
Hopefully someone can have a look and let me know where I am going wrong.

Code

Private Sub OpenCalRep(date1 As Date)
If date1 = Null Then
DoCmd.OpenForm "frmmaintenance", , , , acFormAdd
Forms!frmmaintenance.txtDate = Forms!frmcalsite.txtDate
Else
DoCmd.OpenReport "rptmaintenance", acViewPreview, , "Tables!tblmaintenance.txtdate" = "forms!frmcalmain.sf1.form!txtdate"
End If

End Sub

I realise that there is no counter to increment the subform name yet (SF1, SF2, etc) but I want to get the code to work for just the first box initially so I know that I'm heading in the right direction.

This code is the prefilled from the subform by using:

Private Sub SF1_Enter()
OpenCalRep (Forms!frmcalmain.SF1.Form!txtDate)
End Sub

I realise that there is no counter to increment the subform name yet (SF1, SF2, etc) but I want to get the code to work for just the first box initially so I know that I'm heading in the right direction.

Regards

Jason