Using an OSGi Bundle from a Java Web Application in Tomcat

I am trying to invoke a method of an OSGi bundle from a Java Web Application. Both are supposed to run on Tomcat 7.

I already wrote a normal Java application that invokes methods from the OSGi bundle, as described on this site: http://drupal.osgibook.org/node/37.

To get the context of the Equinox environment I started it from the application and installed the bundles from within. Furthermore the context was used to retrieve a service reference of the running bundle and getting its service.

The runEquinox method of the EquinoxRunner class:

import org.osgi.framework.Bundle;
import org.osgi.framework.BundleContext;

public BundleContext runEquinox([...]) throws Exception {
    [...]

    BundleContext bundleContext = EclipseStarter.startup(new String[]{"-console"}, null);
    bundleContext.installBundle("file:C:/.../plugins/myosgiclass.interface_1.0.0.201108301327.jar");
    Bundle bundleTranslationImpl =  bundleContext.installBundle("file:C:/.../plugins/myosgiclass.impl_1.0.0.201108301327.jar");
    bundleTranslationImpl.start();

    [...]
    return bundleContext;
}

and the invokeMethod of the ServiceRunner class:

import org.osgi.framework.BundleContext;
import org.osgi.framework.ServiceReference;

[...]

public Object invokeMethod(BundleContext bundleContext, Object value, [...]){
    ServiceReference serviceReference = bundleContext.getServiceReference(MyOSGiClass.class.getName());
    Object result = null;
    if (serviceReference != null) {
        MyOSGiClass myOSGiClass = (MyOSGiClass) bundleContext.getService(serviceReference);
        if (myOSGiClass != null) result = myOSGiClass.method(value);
        bundleContext.ungetService(serviceReference);
    }
    return result;
}

Now, on Tomcat using the eclipse bridge, I don't know how to retrieve the right context of the Equinox environment. When I try running it on Tomcat with Equinox I get NoClassDefFound Exceptions. I would appreciate any advice on how to solve this problem.

Thanks a lot in advance. Cheers, Nic