Focus on SAP window using VBA

Hi im back again.
Now I beg for help with focusing on another window during script being processed. Its SAP window. For SAP franchise its SAP ARP - transaction CO02 - change of order - adding an attachment. Im in the final step where small import window pops up and I just need to insert or search for the path of the file I want to add. Its kind of microsoft window - on the left are large buttons with desktop, documents and 2-3 more. But its called Import on the left upper corner. I want to use the sendkeys prompt - the path will be allways the same eg C:\File\xxx.pdf. So I thought it will be very easy just call the macro recorded in sap until the window shows, then sendkeys "C:\File\xxx.pdf" then continue with SAP macro to okay it and save - end.
Problem is when the window show and I sendkeys - it does not write anything in path box. When i run the macro until the window shows and type something on kb it write normally in the box.

Can somebody help me please with this? Ive tried an application"focus" ("microsoft") prompt (quotes are for I cant remember the exact phrase I dont have the excel and file with macro here) It does not help... maybe because its not windows window but SAP window.
Windows 7, Office 2007, work computer - so I dont have access to all OS features, but I think it does not matter.

Thanks very much for your replies.
Mirek