Hi Timo,
yes, it is possible to use LabVIEW as an ActiveX Server (this is a part of the LabVIEW Intermediate 2 course). The first thing I found is an Excel example within the LabVIEW directory (C:\Programme\National Instruments\LabVIEW X.X\examples\comm\frequency.xls), that shows how to access LabVIEW using VBA.
I also found the following helpful links on the internet (ni.com):
1. Enabling LabVIEW as an ActiveX Server:
http://digital.ni.com/public.nsf/websearch/0AA13C1B5D6C215F862565BC006E072F?OpenDocument
2. Functionality Provided by LabVIEW as an ActiveX Server:
http://digital.ni.com/public.nsf/websearch/930F65A05E498BC0862566F10045F9CF?OpenDocument
3. Calling a LabVIEW VI with the LabVIEW ActiveX Automation Server:
http://zone.ni.com/devzone/cda/epd/p/id/750
The one thing, that I/we don't know is how to call LabVIEW from MatLab. Please check your Matlab Manual or ask MathWorks for support on this issue.
Another thing would be to purchase for the NI LabVIEW Math Interface Toolkit, which allows you to integrate LabVIEW Applications into Matlab:
http://sine.ni.com/nips/cds/view/p/lang/de/nid/12922
Another possibility would be to integrate your Matlab code into LabVIEW, by using a MathScript Node (Functions Palette >> Programming >> Structures). But this is only possible with the LabVIEW Full Development system with MathScript and the LabVIEW Professional Development System with MathScript. You can't buy the MathScript support as a Toolkit or Module. You have to upgrade your current LabVIEW version to one of the two previous mentioned versions:
http://www.ni.com/labview/d/mathscript.htm
I hope this helps...
Bye
Daniel
NIG