Template class as static property problem

Hi

I have been trying to write a class which could serve as a cache
manager for objects.

file Cache.h
-------------------
class CachedObject;

template<typename T>
class Cache {
public:
    unsigned int cache_size;
    unsigned int cache_counter;
    CachedObject **objects_cache;
    Cache() {
        this->cache_size = 5;
        objects_cache = new CachedObject*[this->cache_size];
    };
    CachedObject *GetInstance() {
        //return new T();
        if (this->cache_counter > 0) {
            return objects_cache[--cache_counter];
        } else {
            return new T();
        }
    }
    void AddCacheOrFree(CachedObject *o) { delete o; }
    virtual ~Cache() {delete [] objects_cache;}
};

file CachedObject.h
----------------------------
#include "Cache.h"

class CachedObject {
public:
    static Cache<CachedObject> myCache;
    CachedObject() {};
    void Destroy() {
        CachedObject::myCache.AddCacheOrFree(this);
    }
    virtual ~CachedObject() {};
};

file main.cpp
------------------
#include "CachedObject.h"

int main(int argc, char* argv[]) {
    CachedObject *myCachedObject = CachedObject::myCache.GetInstance();
    myCachedObject->Destroy();
    return 0;
}

It does not compile and gives linker error "main.o:main.cpp:(.text
+0xf): undefined reference to `CachedObject::myCache'".
If I uncomment //return new T(); in GetInstance it compiles without
errors.
I can't figure out what I am doing wrong. Could you help?

Oh another concern... If I had declared constructor as

Cache(int i) { ... .... }

how could I declare property

static Cache<CachedObject> myCache;

Thanks in advance for answer.
Regards
Michal Mierzwa